Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Fair Value Measurements (Details)

v3.6.0.2
Employee Benefit Plans - Fair Value Measurements (Details) - USD ($)
$ in Millions
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets $ 23,772 $ 23,505    
Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 12,483 13,843    
Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 10,260 8,625    
Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,029 1,037 $ 962 $ 879
Money market and interest-bearing cash        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 776 3,061    
Money market and interest-bearing cash | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 776 3,061    
Money market and interest-bearing cash | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Money market and interest-bearing cash | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Cash and cash equivalent commingled/mutual funds        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 997 4    
Cash and cash equivalent commingled/mutual funds | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Cash and cash equivalent commingled/mutual funds | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 997 4    
Cash and cash equivalent commingled/mutual funds | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
U.S. government and agency securities        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 3,951 3,615    
U.S. government and agency securities | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 3,125 2,723    
U.S. government and agency securities | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 816 881    
U.S. government and agency securities | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 10 11 11 12
Corporate debt securities        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,892 1,795    
Corporate debt securities | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Corporate debt securities | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,892 1,795    
Corporate debt securities | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Asset-backed securities        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 2,246 1,939    
Asset-backed securities | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Asset-backed securities | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 2,246 1,939    
Asset-backed securities | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Non-U.S. debt securities        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,494 1,294    
Non-U.S. debt securities | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 789 632    
Non-U.S. debt securities | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 705 662    
Non-U.S. debt securities | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0 0 6
Fixed income commingled/mutual funds        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 2,281 1,972    
Fixed income commingled/mutual funds | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 778 551    
Fixed income commingled/mutual funds | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,503 1,421    
Fixed income commingled/mutual funds | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Common and preferred equity securities        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 6,120 6,735    
Common and preferred equity securities | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 6,120 6,735    
Common and preferred equity securities | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Common and preferred equity securities | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Equity commingled/mutual funds        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,960 1,506    
Equity commingled/mutual funds | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 735 3    
Equity commingled/mutual funds | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 1,225 1,503    
Equity commingled/mutual funds | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Public real estate investment trusts        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 145 138    
Public real estate investment trusts | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 145 138    
Public real estate investment trusts | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Public real estate investment trusts | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Private real estate        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 150 144    
Private real estate | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Private real estate | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Private real estate | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 150 144 127 119
Real estate commingled/mutual funds        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 760 743    
Real estate commingled/mutual funds | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Real estate commingled/mutual funds | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 12 12    
Real estate commingled/mutual funds | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 748 731 632 462
Limited partnerships        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 170 170    
Limited partnerships | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 0 0    
Limited partnerships | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 132 121    
Limited partnerships | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 38 49 65 145
Other investments        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 830 389    
Other investments | Level 1        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 15 0    
Other investments | Level 2        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 732 287    
Other investments | Level 3        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 83 102 $ 127 $ 135
Interest Rate Swap        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 257 114    
Participant Loans        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 36 58    
Commodity and Balanced Funds        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets 369 165    
Other Various Investments        
Defined Benefit Plan Disclosure [Line Items]        
Fair value of plan assets $ 168 $ 52