Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Jul. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Jul. 31, 2018	Sep. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to Successor/Predecessor		$ 1,020	$ 84		$ (189)
Less: Undistributed earnings attributable to participating stockholders		9	1		0
Net income (loss) attributable to common stockholders		$ 1,011	$ 83		$ (189)
Net income (loss) per common share attributable to Successor/Predecessor:
Basic (in dollars per share)		$ 11.13	$ 0.91		$ (2.08)
Diluted (in dollars per share)		$ 10.99	$ 0.90		$ (2.08)
Weighted average shares of common stock outstanding (in thousands):
Basic (in shares)		90,808	91,080		91,012
Dilutive effect of stock awards (in shares)		345	117		0
Dilutive effect of participating securities (in shares)		839	839		0
Diluted (in shares)		91,992	92,036		91,012
Nationstar Mortgage Holdings Inc.
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to Successor/Predecessor	$ (64)			$ 154
Less: Undistributed earnings attributable to participating stockholders	0			0
Net income (loss) attributable to common stockholders	$ (64)			$ 154
Net income (loss) per common share attributable to Successor/Predecessor:
Basic (in dollars per share)	$ (0.65)			$ 1.57
Diluted (in dollars per share)	$ (0.65)			$ 1.55
Weighted average shares of common stock outstanding (in thousands):
Basic (in shares)	98,164			98,046
Dilutive effect of stock awards (in shares)	0			1,091
Dilutive effect of participating securities (in shares)	0			0
Diluted (in shares)	98,164			99,137