Other Assets - Schedule of Others Assets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Loans subject to repurchase right from Ginnie Mae	$ 468	$ 560
Derivative financial instruments	294	153
Trade receivables and accrued revenues	143	126
Goodwill	120	120
Right-of-use assets	111	121
Intangible assets	61	74
Other	372	236
Total other assets	$ 1,569	$ 1,390