Income Taxes (Analysis of the Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States	$ 523	$ 223	$ 350
State	53	56	48
Other countries	361	394	387
Total	937	673	785
United States	(40)	(180)	67
State	31	(74)	(16)
Other countries	(6)	(1)	20
Total	(15)	(255)	71
Total provision for income taxes	$ 922	$ 418	$ 856