Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 2,746,000,000	$ 2,555,000,000
Goodwill acquired during the year	21,000,000	188,000,000
Adjustments to prior year acquisitions	14,000,000	3,000,000
Pacific Union Sale	(52,000,000)
Impairment	(3,000,000)	0
Goodwill, ending balance	2,726,000,000	2,746,000,000
Corporate and Other
Goodwill [Roll Forward]
Goodwill, beginning balance	314,000,000	210,000,000
Goodwill acquired during the year	3,000,000	104,000,000
Adjustments to prior year acquisitions	2,000,000	0
Pacific Union Sale	(52,000,000)
Impairment	(3,000,000)
Goodwill, ending balance	264,000,000	314,000,000
Operating Segments
Goodwill [Roll Forward]
Goodwill, beginning balance		2,345,000,000
Operating Segments | Title
Goodwill [Roll Forward]
Goodwill, beginning balance	2,432,000,000	2,345,000,000
Goodwill acquired during the year	18,000,000	84,000,000
Adjustments to prior year acquisitions	12,000,000	3,000,000
Pacific Union Sale	0
Impairment	0
Goodwill, ending balance	$ 2,462,000,000	$ 2,432,000,000