Annual report pursuant to Section 13 and 15(d)

Long-term Debt Long-term Debt - Trust Securities Summary (Details)

v3.6.0.2
Long-term Debt Long-term Debt - Trust Securities Summary (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2016
USD ($)
Junior subordinated notes  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 4,773
Junior subordinated notes | Capital Trust VI  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 27
Per Annum Interest Rate of the Notes 5.63%
Junior subordinated notes | Capital Trust VII  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 5
Per Annum Interest Rate of the Notes 5.25%
Junior subordinated notes | Capital Trust XI  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 678
Per Annum Interest Rate of the Notes 6.63%
Junior subordinated notes | Capital Trust XV  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 1
Junior subordinated notes | Capital Trust III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes 136
Junior subordinated notes | Capital III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes 106
Junior subordinated notes | Capital Trust V  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes 82
Junior subordinated notes | Capital Trust III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes 55
Junior subordinated notes | Capital Trust IV  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes 106
Junior subordinated notes | Capital Trust B  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes 73
Junior subordinated notes | Capital III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 206
Per Annum Interest Rate of the Notes 8.05%
Junior subordinated notes | Capital V  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 1,496
Per Annum Interest Rate of the Notes 7.00%
Junior subordinated notes | Capital Trust I  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 1,051
Per Annum Interest Rate of the Notes 6.45%
Junior subordinated notes | Capital Trust III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of the Notes $ 751
Per Annum Interest Rate of the Notes 7.375%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital Trust XV  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 0.80%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital Trust III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 0.55%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 0.57%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital Trust V  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 1.00%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital Trust III  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 0.75%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital Trust IV  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 0.60%
Junior subordinated notes | 3-Month London Interbank Offered Rate (LIBOR) | Capital Trust B  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Basis spread on variable rate 0.80%
Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities $ 4,724
Capital Trust VI | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 27
Capital Trust VII | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 5
Capital Trust XI | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 658
Capital Trust XV | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 1
Capital Trust III | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 131
Capital III | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 103
Capital Trust V | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 79
Capital Trust III | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 53
Capital Trust IV | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 102
Capital Trust B | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 70
Capital III | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 200
Capital V | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 1,495
Capital Trust I | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities 1,050
Capital Trust III | Trust Preferred Securities Subject to Mandatory Redemption  
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]  
Aggregate Principal Amount of Trust Securities $ 750