Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	$ (1,827)	$ (1,493)	$ (2,039)	$ (2,035)
Other comprehensive income (loss) before reclassifications	334	(112)	505	429
Amounts reclassified from accumulated other comprehensive (income) loss	22	(28)	63	(27)
Other comprehensive income (loss)	356	(140)	568	402
Accumulated other comprehensive income (loss), end of period	(1,471)	(1,633)	(1,471)	(1,633)
Foreign currency translation
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(1,823)	(1,545)	(1,970)	(1,953)
Other comprehensive income (loss) before reclassifications	324	(103)	469	305
Amounts reclassified from accumulated other comprehensive (income) loss	0	0	2	0
Other comprehensive income (loss)	324	(103)	471	305
Accumulated other comprehensive income (loss), end of period	(1,499)	(1,648)	(1,499)	(1,648)
Pension and other postretirement benefits
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	18	39	14	(69)
Other comprehensive income (loss) before reclassifications	0	(1)	8	117
Amounts reclassified from accumulated other comprehensive (income) loss	(4)	(9)	(8)	(19)
Other comprehensive income (loss)	(4)	(10)	0	98
Accumulated other comprehensive income (loss), end of period	14	29	14	29
Derivative financial instruments
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(65)	(32)	(115)	(50)
Other comprehensive income (loss) before reclassifications	0	(18)	10	(9)
Amounts reclassified from accumulated other comprehensive (income) loss	26	1	66	10
Other comprehensive income (loss)	26	(17)	76	1
Accumulated other comprehensive income (loss), end of period	(39)	(49)	(39)	(49)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	43	45	32	37
Other comprehensive income (loss) before reclassifications	10	10	18	16
Amounts reclassified from accumulated other comprehensive (income) loss	0	(20)	3	(18)
Other comprehensive income (loss)	10	(10)	21	(2)
Accumulated other comprehensive income (loss), end of period	$ 53	$ 35	$ 53	$ 35