Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	$ 5,228
Ending balance	5,222
AOCI
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(1,504)	$ (658)
Ending balance	(1,332)	(1,226)
Accumulated Foreign Currency Translation Adjustment
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss) adjustments during the period	124	(527)
Other comprehensive income (loss), adjustments reclassified to income	1	0
Income taxes	39	(50)
Other comprehensive income (loss), net of tax	164	(577)
Accumulated Pension and Other Postretirement Benefit Adjustments
Changes in Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss) adjustments during the period	1	(2)
Other comprehensive income (loss), adjustments reclassified to income	11	15
Income taxes	(4)	(4)
Other comprehensive income (loss), net of tax	$ 8	$ 9