Reverse Mortgage Interests, Net - Reserves Roll Forward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reverse Mortgage Interests Reserves [Roll Forward]
Balance - beginning of period	$ 13
Provision	0
Write-offs	5
Balance - end of period	$ 8
Predecessor
Reverse Mortgage Interests Reserves [Roll Forward]
Balance - beginning of period		$ 115
Provision		26
Write-offs		7
Balance - end of period		$ 134