Provision for Income Taxes (Schedule of Current and Deferred Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Current U.S. federal tax expense (benefit), on continuing operations	$ 218	$ 656	$ 32
Current U.S. state and local tax expense (benefit), on continuing operations	7	38	(7)
Current international tax expense (benefit), on continuing operations	466	449	598
Total current tax expense, on continuing operations	691	1,143	623
Deferred U.S. federal tax expense (benefit), on continuing operations	139	91	(205)
Deferred U.S. state and local tax expense (benefit), on continuing operations	4	(42)	(65)
Deferred international tax expense (benefit), on continuing operations	(138)	(24)	7
Total deferred tax expense (benefit), on continuing operations	5	25	(263)
Provision for income taxes on continuing operations	$ 696	$ 1,168	$ 360