Supplemental Cash Flow (Noncash Investing and Financing Activities) (Detail) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Interest paid
Interest	$ 556	$ 481
Income taxes paid, net
Income taxes	439	605
Transfers:
Portfolio loans to loans held for sale	152	153
Loans held for sale to portfolio loans	11	20
Portfolio loans to OREO	$ 28	$ 39

Transfer of loans held in the portfolio to OREO during the period

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- Definition

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

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Amount of cash paid for interest. Includes, but is not limited to, payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

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- Definition

Value of loans held-for-sale transferred to loans held in the entity's portfolio in noncash transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

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Value of loans and leases held in the entity's portfolio transferred to loans and leases held-for-sale in noncash transactions.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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