Fair Value Measurements - Carrying Amounts and Estimated Fair Values of Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Millions		Mar. 31, 2022	Dec. 31, 2021
Carrying Amount
Assets:
Cash and cash equivalents		$ 1,704	$ 1,228
Deposits with banks		56	58
Notes receivable, net		11	32
Secured financings receivable		606	565
Loans eligible for repurchase		36	47
Liabilities:
Secured financings payable	[1]	547	529
Liability for loans eligible for repurchase		36	47
Notes and contracts payable		1,647	1,648
Estimated Fair Value
Assets:
Cash and cash equivalents		1,704	1,228
Deposits with banks		56	58
Notes receivable, net		11	32
Secured financings receivable		606	565
Loans eligible for repurchase		36	47
Liabilities:
Secured financings payable	[1]	547	529
Liability for loans eligible for repurchase		36	47
Notes and contracts payable		1,595	1,724
Estimated Fair Value | Level 1
Assets:
Cash and cash equivalents		1,704	1,228
Deposits with banks		9	13
Notes receivable, net		0	0
Secured financings receivable		0	0
Loans eligible for repurchase		0	0
Liabilities:
Secured financings payable	[1]	0	0
Liability for loans eligible for repurchase		0	0
Notes and contracts payable		0	0
Estimated Fair Value | Level 2
Assets:
Cash and cash equivalents		0	0
Deposits with banks		47	45
Notes receivable, net		0	0
Secured financings receivable		606	565
Loans eligible for repurchase		36	47
Liabilities:
Secured financings payable	[1]	547	529
Liability for loans eligible for repurchase		36	47
Notes and contracts payable		1,591	1,720
Estimated Fair Value | Level 3
Assets:
Cash and cash equivalents		0	0
Deposits with banks		0	0
Notes receivable, net		11	32
Secured financings receivable		0	0
Loans eligible for repurchase		0	0
Liabilities:
Secured financings payable	[1]	0	0
Liability for loans eligible for repurchase		0	0
Notes and contracts payable		$ 4	$ 4

[1] Excludes servicing related liabilities, which are measured at fair value on a recurring basis.