Loans and Allowance for Loan Losses (Details 14) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Loan impairment
Average Recorded Investment	$ 545	$ 573	$ 535	$ 578
Recognized Interest Income	4	2	14	16
Net transfer of loans held for investment to loans held for sale			867	96
Loan losses allowance
Sale of Loans Held-for-investment			860	84
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	327	189	708	788
Total, excluding purchased credit impaired loans
Loan impairment
Average Recorded Investment	543	571	533	576
Recognized Interest Income	4	2	14	16
Commercial portfolio
Loan impairment
Average Recorded Investment	219	236	205	239
Recognized Interest Income	1	0	5	7
Commercial portfolio \| Commercial and industrial
Loan impairment
Average Recorded Investment	191	203	174	204
Recognized Interest Income	1	0	4	4
Commercial portfolio \| Commercial mortgage
Loan impairment
Average Recorded Investment	28	33	31	35
Recognized Interest Income	0	0	1	2
Commercial portfolio \| Construction
Loan impairment
Average Recorded Investment	0	0	0	0
Recognized Interest Income	0	0	0	1
Consumer portfolio
Loan impairment
Average Recorded Investment	324	335	328	337
Recognized Interest Income	3	2	9	9
Consumer portfolio \| Residential mortgage
Loan impairment
Average Recorded Investment	295	307	298	310
Recognized Interest Income	3	2	8	8
Consumer portfolio \| Home equity and other consumer loans
Loan impairment
Average Recorded Investment	29	28	30	27
Recognized Interest Income	0	0	1	1
Purchased credit-impaired loans
Loan impairment
Average Recorded Investment	2	2	2	2
Recognized Interest Income	$ 0	$ 0	0	0
Commercial Loan
Loan impairment
Net transfer of loans held for investment to loans held for sale				$ 96
Consumer
Loan impairment
Net transfer of loans held for investment to loans held for sale			583
Loan losses allowance
Proceeds from Sale and Collection of Loans Held-for-sale			$ 597

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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