Securities (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Securities available for sale
Amortized Cost	$ 12,993	$ 14,470
Gross Unrealized Gains	94	57
Gross Unrealized Losses	76	183
Fair Value	13,011	14,344
U.S. Treasury
Securities available for sale
Amortized Cost	148	596
Gross Unrealized Gains	4	1
Gross Unrealized Losses	0	3
Fair Value	152	594
Residential mortgage-backed securities, U.S. government agency and government-sponsored agencies
Securities available for sale
Amortized Cost	6,302	7,298
Gross Unrealized Gains	16	1
Gross Unrealized Losses	10	98
Fair Value	6,308	7,201
Residential mortgage-backed securities, Privately issued
Securities available for sale
Amortized Cost	202	150
Gross Unrealized Gains	2	2
Gross Unrealized Losses	1	1
Fair Value	203	151
Privately issued - commercial mortgage-backed securities
Securities available for sale
Amortized Cost	1,469	1,566
Gross Unrealized Gains	24	5
Gross Unrealized Losses	1	25
Fair Value	1,492	1,546
Collateralized loan obligations
Securities available for sale
Amortized Cost	3,267	3,266
Gross Unrealized Gains	0	1
Gross Unrealized Losses	40	34
Fair Value	3,227	3,233
Other Asset Liability Management Securities
Securities available for sale
Amortized Cost	7	7
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	7	7
Asset Liability Management securities
Securities available for sale
Amortized Cost	11,395	12,883
Gross Unrealized Gains	46	10
Gross Unrealized Losses	52	161
Fair Value	11,389	12,732
Other debt securities, Direct bank purchase bonds
Securities available for sale
Amortized Cost	1,560	1,549
Gross Unrealized Gains	45	45
Gross Unrealized Losses	24	22
Fair Value	1,581	1,572
Other debt securities, Other
Securities available for sale
Amortized Cost	32	32
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	0
Fair Value	33	32
Equity securities
Securities available for sale
Amortized Cost	6	6
Gross Unrealized Gains	2	2
Gross Unrealized Losses	0	0
Fair Value	$ 8	$ 8

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
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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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