Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Fair Value Measurements Rollforward (Details)

v3.6.0.2
Employee Benefit Plans - Fair Value Measurements Rollforward (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Change in fair value of plan assets      
Fair value, January 1 $ 23,505    
Fair value, December 31 23,772 $ 23,505  
U.S. government and agency securities      
Change in fair value of plan assets      
Fair value, January 1 3,615    
Fair value, December 31 3,951 3,615  
Non-U.S. debt securities      
Change in fair value of plan assets      
Fair value, January 1 1,294    
Fair value, December 31 1,494 1,294  
Private real estate      
Change in fair value of plan assets      
Fair value, January 1 144    
Fair value, December 31 150 144  
Real estate commingled/mutual funds      
Change in fair value of plan assets      
Fair value, January 1 743    
Fair value, December 31 760 743  
Limited partnerships      
Change in fair value of plan assets      
Fair value, January 1 170    
Fair value, December 31 170 170  
Other investments      
Change in fair value of plan assets      
Fair value, January 1 389    
Fair value, December 31 830 389  
Level 3      
Change in fair value of plan assets      
Fair value, January 1 1,037 962 $ 879
Actual Return on Plan Assets Still Held at the Reporting Date 24 45 31
Purchases, Sales and Settlements (32) 30 56
Transfers out of Level 3 0 0 (4)
Fair value, December 31 1,029 1,037 962
Level 3 | U.S. government and agency securities      
Change in fair value of plan assets      
Fair value, January 1 11 11 12
Actual Return on Plan Assets Still Held at the Reporting Date 0 0 0
Purchases, Sales and Settlements (1) 0 (1)
Transfers out of Level 3 0 0 0
Fair value, December 31 10 11 11
Level 3 | Non-U.S. debt securities      
Change in fair value of plan assets      
Fair value, January 1 0 0 6
Actual Return on Plan Assets Still Held at the Reporting Date     0
Purchases, Sales and Settlements     (2)
Transfers out of Level 3     (4)
Fair value, December 31 0 0 0
Level 3 | Private real estate      
Change in fair value of plan assets      
Fair value, January 1 144 127 119
Actual Return on Plan Assets Still Held at the Reporting Date 1 14 5
Purchases, Sales and Settlements 5 3 3
Transfers out of Level 3 0 0 0
Fair value, December 31 150 144 127
Level 3 | Real estate commingled/mutual funds      
Change in fair value of plan assets      
Fair value, January 1 731 632 462
Actual Return on Plan Assets Still Held at the Reporting Date 21 37 20
Purchases, Sales and Settlements (4) 62 150
Transfers out of Level 3 0 0 0
Fair value, December 31 748 731 632
Level 3 | Limited partnerships      
Change in fair value of plan assets      
Fair value, January 1 49 65 145
Actual Return on Plan Assets Still Held at the Reporting Date (2) (1) 5
Purchases, Sales and Settlements (9) (15) (85)
Transfers out of Level 3 0 0 0
Fair value, December 31 38 49 65
Level 3 | Other investments      
Change in fair value of plan assets      
Fair value, January 1 102 127 135
Actual Return on Plan Assets Still Held at the Reporting Date 4 (5) 1
Purchases, Sales and Settlements (23) (20) (9)
Transfers out of Level 3 0 0 0
Fair value, December 31 $ 83 $ 102 $ 127