Loans and Allowance for Loan Losses - Loans in Consumer Portfolio an Purchased credit-impaired loans (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Consumer portfolio loans
Nonaccrual	$ 404	$ 465
Consumer
Consumer portfolio loans
Loans covered by FDIC loss share agreements	7	8
Accrual	41,276	38,971
Nonaccrual	123	126
Total loans held for investment, before purchased credit-impaired loans	41,399	39,097
Consumer \| Residential Mortgage
Consumer portfolio loans
Total loans held for investment, before purchased credit-impaired loans	37,547	35,638
Consumer \| Home equity and other consumer loans
Consumer portfolio loans
Total loans held for investment, before purchased credit-impaired loans	3,852	3,459
Residential Mortgage \| Consumer Loans Portfolio Segment [Member]
Consumer portfolio loans
Accrual	37,447	35,534
Nonaccrual	100	104
Home equity and other consumer loans \| Consumer Loans Portfolio Segment [Member]
Consumer portfolio loans
Accrual	3,829	3,437
Nonaccrual	$ 23	$ 22

Financing receivable recorded investment accrual status.

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes purchased credit impaired loans.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

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- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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