Investment Securities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Schedule of Trading and Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,262	$ 1,661
Gross Unrealized Gains	17	14
Gross Unrealized Losses	(7)	(3)
Fair Value	2,272	1,672
Agency
Schedule of Trading and Available-for-sale Securities [Line Items]
Amortized Cost	904	925
Gross Unrealized Gains	6	6
Gross Unrealized Losses	(3)	(2)
Fair Value	907	929
Agency-collateralized mortgage obligations
Schedule of Trading and Available-for-sale Securities [Line Items]
Amortized Cost	1,358	734
Gross Unrealized Gains	11	8
Gross Unrealized Losses	(4)	(1)
Fair Value	$ 1,365	741
Municipal obligations
Schedule of Trading and Available-for-sale Securities [Line Items]
Amortized Cost		2
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		$ 2

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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-Publisher FASB

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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