Allowance for Credit Losses on Loans and Leases - Summary of Activity in Allowance for Loan and Lease Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Valuation Allowance [Line Items]
Balance, beginning of period	$ 199	$ 194
Charge-offs	(3)	(4)
Recoveries	2	5
Provision for (recovery of) credit losses	(1)	3
Balance, end of period	197	198
Mortgage Receivable
Valuation Allowance [Line Items]
Balance, beginning of period	178	176
Charge-offs	(3)	(1)
Provision for (recovery of) credit losses	1	1
Balance, end of period	176	176
Other Loans
Valuation Allowance [Line Items]
Balance, beginning of period	21	18
Charge-offs		(3)
Recoveries	2	5
Provision for (recovery of) credit losses	(2)	2
Balance, end of period	$ 21	$ 22