Securities - Schedule of Available For Sale Securities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Securities available for sale
Amortized Cost	$ 14,378	$ 14,485
Gross Unrealized Gains	54	57
Gross Unrealized Losses	291	183
Fair Value	14,141	14,359
U.S. Treasury
Securities available for sale
Amortized Cost	2,625	596
Gross Unrealized Gains	1	1
Gross Unrealized Losses	121	3
Fair Value	2,505	594
U.S. government agency and government-sponsored agencies
Securities available for sale
Amortized Cost	6,814	7,298
Gross Unrealized Gains	3	1
Gross Unrealized Losses	122	98
Fair Value	6,695	7,201
Privately issued
Securities available for sale
Amortized Cost	333	150
Gross Unrealized Gains	1	2
Gross Unrealized Losses	7	1
Fair Value	327	151
Privately issued - commercial mortgage-backed securities
Securities available for sale
Amortized Cost	666	1,566
Gross Unrealized Gains	4	5
Gross Unrealized Losses	6	25
Fair Value	664	1,546
Collateralized loan obligations
Securities available for sale
Amortized Cost	2,219	3,266
Gross Unrealized Gains	4	1
Gross Unrealized Losses	5	34
Fair Value	2,218	3,233
Other
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	12,664	12,883
Gross Unrealized Gains	13	10
Gross Unrealized Losses	261	161
Fair Value	12,416	12,732
Direct bank purchase bonds
Securities available for sale
Amortized Cost	1,601	1,549
Gross Unrealized Gains	41	45
Gross Unrealized Losses	29	22
Fair Value	1,613	1,572
Other
Securities available for sale
Amortized Cost	108	47
Gross Unrealized Gains	0	0
Gross Unrealized Losses	1	0
Fair Value	107	47
Equity securities
Securities available for sale
Amortized Cost	5	6
Gross Unrealized Gains	0	2
Gross Unrealized Losses	0	0
Fair Value	$ 5	$ 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
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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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