Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	$ (2,039)	$ (2,035)
Other comprehensive income (loss) before reclassifications	171	541
Amounts reclassified from accumulated other comprehensive (income) loss	41	1
Other comprehensive income (loss)	212	542
Accumulated other comprehensive income (loss), end of period	(1,827)	(1,493)
Foreign currency translation
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(1,970)	(1,953)
Other comprehensive income (loss) before reclassifications	145	408
Amounts reclassified from accumulated other comprehensive (income) loss	2	0
Other comprehensive income (loss)	147	408
Accumulated other comprehensive income (loss), end of period	(1,823)	(1,545)
Pension and other postretirement benefits
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	14	(69)
Other comprehensive income (loss) before reclassifications	8	118
Amounts reclassified from accumulated other comprehensive (income) loss	(4)	(10)
Other comprehensive income (loss)	4	108
Accumulated other comprehensive income (loss), end of period	18	39
Derivative financial instruments
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(115)	(50)
Other comprehensive income (loss) before reclassifications	10	9
Amounts reclassified from accumulated other comprehensive (income) loss	40	9
Other comprehensive income (loss)	50	18
Accumulated other comprehensive income (loss), end of period	(65)	(32)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	32	37
Other comprehensive income (loss) before reclassifications	8	6
Amounts reclassified from accumulated other comprehensive (income) loss	3	2
Other comprehensive income (loss)	11	8
Accumulated other comprehensive income (loss), end of period	$ 43	$ 45