Allowance for Credit Losses - Schedule of Allowance for Credit Losses on Unfunded Commitments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning balance	$ 178	$ 225
Provision (benefit) for credit losses - unfunded commitments	401	(11)
Allowance for credit losses, ending balance	848	211
Financing assets (excluding leases)
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning balance	12	13
Provision (benefit) for credit losses - unfunded commitments	63	(1)
Allowance for credit losses, ending balance	$ 75	$ 12