Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Condensed Consolidated Statements of Comprehensive Income [Abstract]
Net Income	$ 302us-gaap_NetIncomeLoss	$ 326us-gaap_NetIncomeLoss
Change in net unrealized gain on securities available for sale:
Net unrealized gain	107	159
Other reclassifications included in other revenue		(1)
Other comprehensive income, before tax	107	158
Income tax effect	(41)us-gaap_OtherComprehensiveIncomeLossTax	(59)us-gaap_OtherComprehensiveIncomeLossTax
Other comprehensive income, net of tax	66	99
Comprehensive Income	$ 368us-gaap_ComprehensiveIncomeNetOfTax	$ 425us-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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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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