Other Assets - Schedule of Others Assets (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Loans subject to repurchase right from Ginnie Mae	$ 1,171	$ 560
Derivative financial instruments	391	153
Trade receivables and accrued revenues	133	126
Goodwill	120	120
Operating lease right-of-use assets	108	121
Intangible assets	54	74
Other	197	236
Total other assets	$ 2,174	$ 1,390