Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	$ (2,035)	$ (1,059)
Other comprehensive income (loss) before reclassifications	541	(792)
Amounts reclassified from accumulated other comprehensive (income) loss	1	13
Other comprehensive income (loss)	542	(779)
Accumulated other comprehensive income (loss), end of period	(1,493)	(1,838)
Foreign currency translation
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(1,953)	(992)
Other comprehensive income (loss) before reclassifications	408	(786)
Amounts reclassified from accumulated other comprehensive (income) loss	0	0
Other comprehensive income (loss)	408	(786)
Accumulated other comprehensive income (loss), end of period	(1,545)	(1,778)
Pension and other postretirement benefits
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(69)	(31)
Other comprehensive income (loss) before reclassifications	118	0
Amounts reclassified from accumulated other comprehensive (income) loss	(10)	(9)
Other comprehensive income (loss)	108	(9)
Accumulated other comprehensive income (loss), end of period	39	(40)
Derivative financial instruments
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	(50)	(119)
Other comprehensive income (loss) before reclassifications	9	(14)
Amounts reclassified from accumulated other comprehensive (income) loss	9	24
Other comprehensive income (loss)	18	10
Accumulated other comprehensive income (loss), end of period	(32)	(109)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Accumulated other comprehensive income (loss), start of period	37	83
Other comprehensive income (loss) before reclassifications	6	8
Amounts reclassified from accumulated other comprehensive (income) loss	2	(2)
Other comprehensive income (loss)	8	6
Accumulated other comprehensive income (loss), end of period	$ 45	$ 89