Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidated Statements of Comprehensive Income [Abstract]
Net Income	$ 1,321us-gaap_NetIncomeLoss	$ 1,071us-gaap_NetIncomeLoss	$ 928us-gaap_NetIncomeLoss
Change in net unrealized gain on securities available for sale:
Net unrealized gain (loss)	255	(468)	470
Reclassification of impairment charges included in net impairment losses on securities	1	10	32
Other reclassifications included in other revenue	(7)	(7)	(38)
Other		1	1
Other comprehensive income (loss), before tax	249	(464)	465
Income tax effect	(93)us-gaap_OtherComprehensiveIncomeLossTax	175us-gaap_OtherComprehensiveIncomeLossTax	(175)us-gaap_OtherComprehensiveIncomeLossTax
Other comprehensive income (loss), net of tax	156	(289)	290
Comprehensive Income	$ 1,477us-gaap_ComprehensiveIncomeNetOfTax	$ 782us-gaap_ComprehensiveIncomeNetOfTax	$ 1,218us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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