Postretirement Benefit Plans - Amounts Recognized in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined benefit plan amounts recognized in other comprehensive income roll forward
AOCI balance, net actuarial loss portion (net of taxes), beginning of period	$ 529
Adjustments, net actuarial loss	110
Recognized within Net income, net actuarial loss	(78)
Tax effect, net actuarial loss	(11)
Total change to AOCI, net actuarial loss	21
AOCI balance, net actuarial loss portion (net of taxes), period end	550	$ 529
Defined benefit plan amounts recognized in other comprehensive income prior service cost (credit) portion roll forward
AOCI balance, net prior service cost (credit) (net of taxes), beginning of period	0
Adjustments, prior service cost (credit)	(31)
Recognized within Net income, prior service cost (credit)	0
Tax effect, prior service cost (credit)	11	0	$ (1)
Total change to AOCI, prior service cost	(20)
AOCI balance, net prior service cost (credit) (net of taxes), period end	(20)	0
U.S. defined benefit plan
Defined benefit plan amounts recognized in other comprehensive income roll forward
AOCI balance, net actuarial loss portion (net of taxes), beginning of period	153
Adjustments, net actuarial loss	65
Recognized within Net income, net actuarial loss	(43)
Tax effect, net actuarial loss	(8)
Total change to AOCI, net actuarial loss	14
AOCI balance, net actuarial loss portion (net of taxes), period end	167	153
U.S. retiree health care plan
Defined benefit plan amounts recognized in other comprehensive income roll forward
AOCI balance, net actuarial loss portion (net of taxes), beginning of period	85
Adjustments, net actuarial loss	0
Recognized within Net income, net actuarial loss	(8)
Tax effect, net actuarial loss	3
Total change to AOCI, net actuarial loss	(5)
AOCI balance, net actuarial loss portion (net of taxes), period end	80	85
Defined benefit plan amounts recognized in other comprehensive income prior service cost (credit) portion roll forward
AOCI balance, net prior service cost (credit) (net of taxes), beginning of period	8
Adjustments, prior service cost (credit)	(30)
Recognized within Net income, prior service cost (credit)	(2)
Tax effect, prior service cost (credit)	11
Total change to AOCI, prior service cost	(21)
AOCI balance, net prior service cost (credit) (net of taxes), period end	(13)	8
Non-U.S. defined benefit plan
Defined benefit plan amounts recognized in other comprehensive income roll forward
AOCI balance, net actuarial loss portion (net of taxes), beginning of period	291
Adjustments, net actuarial loss	45
Recognized within Net income, net actuarial loss	(27)
Tax effect, net actuarial loss	(6)
Total change to AOCI, net actuarial loss	12
AOCI balance, net actuarial loss portion (net of taxes), period end	303	291
Defined benefit plan amounts recognized in other comprehensive income prior service cost (credit) portion roll forward
AOCI balance, net prior service cost (credit) (net of taxes), beginning of period	(8)
Adjustments, prior service cost (credit)	(1)
Recognized within Net income, prior service cost (credit)	2
Tax effect, prior service cost (credit)	0
Total change to AOCI, prior service cost	1
AOCI balance, net prior service cost (credit) (net of taxes), period end	$ (7)	$ (8)