Loans and Allowance for Loan Losses (Details 14) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Loan impairment
Average Recorded Investment	$ 448	$ 542	$ 386	$ 529
Recognized Interest Income	2	4	7	10
Net transfer of loans held for investment to loans held for sale			179	202
Loan losses allowance
Sale of Loans Held-for-investment			112	198
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	432	112	720	381
Total, excluding purchased credit impaired loans
Loan impairment
Average Recorded Investment	447	540	385	527
Recognized Interest Income	2	4	7	10
Commercial portfolio
Loan impairment
Average Recorded Investment	153	212	87	196
Recognized Interest Income	0	2	2	4
Commercial portfolio \| Commercial and industrial
Loan impairment
Average Recorded Investment	138	183	73	164
Recognized Interest Income	0	1	2	3
Commercial portfolio \| Commercial mortgage
Loan impairment
Average Recorded Investment	15	29	14	32
Recognized Interest Income	0	1	0	1
Commercial portfolio \| Commercial Loan
Loan impairment
Financing Receivable, Reclassification to Held-for-sale			179	207
Consumer portfolio
Loan impairment
Average Recorded Investment	294	328	298	331
Recognized Interest Income	2	2	5	6
Consumer portfolio \| Residential mortgage
Loan impairment
Average Recorded Investment	263	298	267	301
Recognized Interest Income	2	2	4	5
Consumer portfolio \| Home equity and other consumer loans
Loan impairment
Average Recorded Investment	31	30	31	30
Recognized Interest Income	0	0	1	1
Purchased credit-impaired loans
Loan impairment
Average Recorded Investment	1	2	1	2
Recognized Interest Income	$ 0	$ 0	$ 0	$ 0

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831270

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831223

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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