Income Taxes Income Taxes - Reconciliation of Unrecognized Tax Benefits Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of period	$ 280	$ 303	$ 644
Additions based on tax positions related to the current year	0	27	13
Additions to tax positions of prior years	33	0	0
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	(111)	0	0
Reductions to tax positions of prior years	0	(50)	(354)
Unrecognized tax benefits at end of period	$ 202	$ 280	$ 303