Securities - Schedule of Available For Sale Securities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Securities available for sale
Amortized Cost	$ 14,470	$ 13,819
Gross Unrealized Gains	57	76
Gross Unrealized Losses	183	171
Fair Value	14,344	13,724
U.S. Treasury
Securities available for sale
Amortized Cost	596
Gross Unrealized Gains	1
Gross Unrealized Losses	3
Fair Value	594
Residential mortgage-backed securities, U.S. government agency and government-sponsored agencies
Securities available for sale
Amortized Cost	7,298	7,649
Gross Unrealized Gains	1	2
Gross Unrealized Losses	98	91
Fair Value	7,201	7,560
Residential mortgage-backed securities, Privately issued
Securities available for sale
Amortized Cost	150	166
Gross Unrealized Gains	2	3
Gross Unrealized Losses	1	1
Fair Value	151	168
Commercial Mortgage Backed Securities Private Issue [Member]
Securities available for sale
Amortized Cost	1,566	1,689
Gross Unrealized Gains	5	15
Gross Unrealized Losses	25	13
Fair Value	1,546	1,691
Collateralized loan obligations
Securities available for sale
Amortized Cost	3,266	2,527
Gross Unrealized Gains	1	4
Gross Unrealized Losses	34	37
Fair Value	3,233	2,494
Other Asset Liability Management Securities, Other
Securities available for sale
Amortized Cost	7	8
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	7	9
Asset Liability Management securities
Securities available for sale
Amortized Cost	12,883	12,039
Gross Unrealized Gains	10	25
Gross Unrealized Losses	161	142
Fair Value	12,732	11,922
Other debt securities, Direct bank purchase bonds
Securities available for sale
Amortized Cost	1,549	1,719
Gross Unrealized Gains	45	49
Gross Unrealized Losses	22	27
Fair Value	1,572	1,741
Other debt securities, Other
Securities available for sale
Amortized Cost	32	53
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	1
Fair Value	32	52
Equity securities
Securities available for sale
Amortized Cost	6	8
Gross Unrealized Gains	2	2
Gross Unrealized Losses	0	1
Fair Value	$ 8	$ 9

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 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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