Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) payment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Summary of Significant Accounting Policies [Line Items]
Probable loss experience period	10 years
Extension term	6 months
Threshold period for resuming interest accrual on delinquent accounts	60 days
Threshold for delinquent accounts	90 days
Total shareholders' equity	$ 13,794	$ 13,598	$ 12,726	$ 11,659
Cumulative Effect, Period of Adopt
Summary of Significant Accounting Policies [Line Items]
Total shareholders' equity			(643)
Cumulative Effect, Period of Adopt | Accounting Standards Update 2016-13 [Member] | Financing Receivable Allowance for Credit Loss
Summary of Significant Accounting Policies [Line Items]
Total shareholders' equity			(801)
Retained Earnings
Summary of Significant Accounting Policies [Line Items]
Total shareholders' equity	$ 6,375	$ 6,265	5,744	$ 4,667
Retained Earnings | Cumulative Effect, Period of Adopt
Summary of Significant Accounting Policies [Line Items]
Total shareholders' equity			(643)
Retained Earnings | Cumulative Effect, Period of Adopt | Accounting Standards Update 2016-13 [Member]
Summary of Significant Accounting Policies [Line Items]
Total shareholders' equity			$ (643)
Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	1 year
Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life (in years)	30 years
Retail Finance Receivables
Summary of Significant Accounting Policies [Line Items]
Contractually delinquent period	120 days
Number of delinquent payments that can be moved | payment	2
Commercial Finance Receivables
Summary of Significant Accounting Policies [Line Items]
Typical repayment period	90 days
Contractually delinquent period	360 days
Commercial Finance Receivables | Maximum
Summary of Significant Accounting Policies [Line Items]
Payment period after loan is called	60 days