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Premises, Equipment and Leases Premises, Equipment and Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment and Lease Commitments [Abstract]
Depreciation and amortization expense	$ 809	$ 741	$ 728
Finance lease, right-of-use asset	69	96
Finance lease, liability	$ 75	$ 103
Finance leases, a weighted-average remaining lease term	4 years 4 months 24 days	5 years 10 months 24 days
Finance lease expense	$ 24	$ 27

X

- Definition

Finance Lease, Cost

+ References

No definition available.

+ Details

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X

- Definition

Property, Plant and Equipment and Lease Commitments [Abstract]

+ References

No definition available.

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X

- Definition

The expense recognized in the current period that allocates the cost of nonproduction tangible assets over their useful lives.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
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-Section 50
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- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
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X

- Definition

Amount, after accumulated amortization, of right-of-use asset from finance lease.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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X

- Definition

Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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