Fair Value Measurements - Assets and Liabilities Recorded as Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)	$ (62)	$ (1,048)
Consumer loans held for sale
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)	(12)	0
Consumer loans
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)	10	18
Commercial loans held for sale
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)	(17)	(23)
Commercial Loans
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)	60	(169)
Real Estate Owned
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)		2
Goodwill
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)		(784)
Leases
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total Gains (Losses)	(103)	(92)
Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	2,202	658
Fair Value, Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	201	385
Fair Value, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	2,001	273
Fair Value, Nonrecurring | Consumer loans held for sale
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	1,766	4
Fair Value, Nonrecurring | Consumer loans held for sale | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Consumer loans held for sale | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	24	4
Fair Value, Nonrecurring | Consumer loans held for sale | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	1,742	0
Fair Value, Nonrecurring | Consumer loans
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	102	312
Fair Value, Nonrecurring | Consumer loans | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Consumer loans | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	102	312
Fair Value, Nonrecurring | Consumer loans | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Commercial loans held for sale
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	143	68
Fair Value, Nonrecurring | Commercial loans held for sale | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Commercial loans held for sale | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	75	68
Fair Value, Nonrecurring | Commercial loans held for sale | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	68	0
Fair Value, Nonrecurring | Commercial Loans
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	186	270
Fair Value, Nonrecurring | Commercial Loans | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Commercial Loans | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Commercial Loans | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	186	270
Fair Value, Nonrecurring | Real Estate Owned
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		1
Fair Value, Nonrecurring | Real Estate Owned | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		0
Fair Value, Nonrecurring | Real Estate Owned | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		1
Fair Value, Nonrecurring | Real Estate Owned | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		0
Fair Value, Nonrecurring | Goodwill
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		0
Fair Value, Nonrecurring | Goodwill | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		0
Fair Value, Nonrecurring | Goodwill | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		0
Fair Value, Nonrecurring | Goodwill | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		0
Fair Value, Nonrecurring | Leases
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	5	3
Properties held for sale	5
Fair Value, Nonrecurring | Leases | Level 1
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Leases | Level 2
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	0	0
Fair Value, Nonrecurring | Leases | Level 3
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis	$ 5	3
Wealth and Personal Banking | Fair Value, Nonrecurring | Goodwill
Fair Value, Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Total assets at fair value on a non-recurring basis		$ 0