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Employee Benefit Plans - Fair Value of Plan Assets (Details) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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Dec. 31, 2008
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | $ 20,244 | $ 20,136 | ||||||
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Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 9,863 | 10,114 | ||||||
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Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 9,642 | 9,350 | ||||||
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Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 739 | 672 | 670 | 821 | ||||
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Limited Partnerships [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 337 | 331 | ||||||
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Limited Partnerships [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Limited Partnerships [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 105 | 101 | ||||||
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Limited Partnerships [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 232 | 230 | 162 | 91 | ||||
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Other Investments [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 708 | [1] | 343 | [1] | ||||
| Swaps Included In Other Investments | 467 | 198 | ||||||
| Participant Loans Included In Other Investments | 75 | 79 | ||||||
| Commodity And Balance Funds Included In Other Investments | 116 | 38 | ||||||
| Other Various Investments | 50 | 28 | ||||||
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Other Investments [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 14 | [1] | 19 | [1] | ||||
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Other Investments [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 572 | [1] | 230 | [1] | ||||
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Other Investments [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 122 | [1] | 94 | [1] | 188 | 293 | ||
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Money Market And Interest Bearing Cash [Member] | Cash and Cash Equivalents [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,065 | 1,471 | ||||||
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Money Market And Interest Bearing Cash [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,065 | 1,471 | ||||||
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Money Market And Interest Bearing Cash [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Money Market And Interest Bearing Cash [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Mutual Funds [Member] | Cash and Cash Equivalents [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 30 | 45 | ||||||
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Mutual Funds [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Mutual Funds [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 30 | 45 | ||||||
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Mutual Funds [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Mutual Funds [Member] | Fixed Income Investments [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,569 | 1,743 | ||||||
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Mutual Funds [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 82 | 240 | ||||||
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Mutual Funds [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,487 | 1,503 | ||||||
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Mutual Funds [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Mutual Funds [Member] | Equity Securities
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 2,484 | 3,011 | ||||||
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Mutual Funds [Member] | Equity Securities | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 390 | 637 | ||||||
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Mutual Funds [Member] | Equity Securities | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 2,094 | 2,374 | ||||||
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Mutual Funds [Member] | Equity Securities | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Mutual Funds [Member] | Real Estate Investment [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 260 | 247 | ||||||
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Mutual Funds [Member] | Real Estate Investment [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 30 | ||||||
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Mutual Funds [Member] | Real Estate Investment [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 11 | 2 | ||||||
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Mutual Funds [Member] | Real Estate Investment [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 249 | 215 | 195 | 281 | ||||
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US Treasury and Government [Member] | Fixed Income Investments [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 4,109 | 3,319 | ||||||
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US Treasury and Government [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,197 | 701 | ||||||
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US Treasury and Government [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 2,899 | 2,604 | ||||||
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US Treasury and Government [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 13 | 14 | 0 | |||||
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Corporate Debt Securities [Member] | Fixed Income Investments [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,058 | 1,106 | ||||||
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Corporate Debt Securities [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Corporate Debt Securities [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 1,058 | 1,106 | ||||||
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Corporate Debt Securities [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | 0 | 1 | ||||
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Asset-backed Securities [Member] | Fixed Income Investments [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 907 | 796 | ||||||
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Asset-backed Securities [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Asset-backed Securities [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 907 | 796 | ||||||
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Asset-backed Securities [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Non-U.S. sovereign debt [Member] | Fixed Income Investments [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 542 | 465 | ||||||
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Non-U.S. sovereign debt [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 53 | 36 | ||||||
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Non-U.S. sovereign debt [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 479 | 420 | ||||||
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Non-U.S. sovereign debt [Member] | Fixed Income Investments [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 10 | 9 | 6 | 6 | ||||
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Common And Preferred Stocks [Member] | Equity Securities
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 6,862 | 6,981 | ||||||
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Common And Preferred Stocks [Member] | Equity Securities | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 6,862 | 6,980 | ||||||
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Common And Preferred Stocks [Member] | Equity Securities | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 1 | ||||||
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Common And Preferred Stocks [Member] | Equity Securities | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Public Real Estate Investment Trusts [Member] | Equity Securities
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 200 | 168 | ||||||
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Public Real Estate Investment Trusts [Member] | Equity Securities | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 200 | 0 | ||||||
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Public Real Estate Investment Trusts [Member] | Equity Securities | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 168 | ||||||
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Public Real Estate Investment Trusts [Member] | Equity Securities | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Private Real Estate [Member] | Real Estate Investment [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 113 | 110 | ||||||
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Private Real Estate [Member] | Real Estate Investment [Member] | Fair Value, Inputs, Level 1 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Private Real Estate [Member] | Real Estate Investment [Member] | Fair Value, Inputs, Level 2 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | 0 | 0 | ||||||
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Private Real Estate [Member] | Real Estate Investment [Member] | Fair Value, Inputs, Level 3 [Member]
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| Defined Benefit Plan Disclosure [Line Items] | ||||||||
| Fair Value, January 1 | $ 113 | $ 110 | $ 119 | $ 149 | ||||
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