Discontinued Operations and Disposal Groups (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Aug. 02, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	$ 3,722		$ 3,722			$ 5,347
Liabilities of discontinued operations	3,740		3,740			5,203
Net (loss) income from discontinued operations	(11)	$ 27	3	$ 11
Discontinued Operation, Loan Asset Retained	95		95
Discontinued Operation, Loan Liability Retained	91		91
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Champion Mortgage [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restricted cash	65		65			83
Reverse mortgage interests, net	3,705		3,705			5,253
Other	5		5			11
Loss recognized on classification as discontinued operations	(53)		(53)			0
Assets of discontinued operations	3,722		3,722			5,347
Advances and warehouse facilities, net	98		98			505
Payables and other liabilities	208		208			233
Mortgage servicing liabilities	41		41			41
Other nonrecourse debt, net	3,393		3,393			4,424
Liabilities of discontinued operations	3,740		3,740			$ 5,203
Revenue - service related, net	4	9	13	35
Salaries, wages and benefits expense	(7)	(10)	(23)	(32)
General and administrative expense	(14)	33	50	15
Interest income	31	40	118	136
Interest expense	(26)	(37)	(90)	(140)
Loss on classification as discontinued operations	(3)	0	(64)	0
(Loss) income from discontinued operations before income tax (benefit) expense	(15)	35	4	14
Less: Income tax (benefit) expense	(4)	8	1	3
Net (loss) income from discontinued operations	(11)	$ 27	3	$ 11
Disposal Group, Discontinued Operation, Transaction Cost	$ 0		$ 5
Disposal Group, Including Discontinued Operation, Net Assets Transferred					$ 1,039