Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Taxes (Textuals) [Abstract]
Tax Expense	$ 126	$ 100	$ 369	$ 168
Income before Income Taxes	431	299	1,118	561
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount		47		47
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount		37		37
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 11		$ 11
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	8
Deferred Tax Asset Valuation Allowance Release Reasonably Possible Tax Benefit	300		300
Unrecognized tax benefits					$ 81
Favorable impact of unrecognized tax benefits if recognized					65
Accrued interest					15
Unsettled unrecognized tax benefits that would require cash					$ 26
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	13		13
Accrued Interest Favorably Settled In Next Twelve Months	$ 5		$ 5