BASIS OF PRESENTATION Narrative (Details) - USD ($) $ in Millions				12 Months Ended
		Jan. 01, 2019	Aug. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill				$ 6,923	$ 6,887	$ 6,876
Purchase price allocation adjustment	[1]			23
Franklin American Mortgage Company
Business Acquisition [Line Items]
Consideration transferred			$ 582
Goodwill			59	36
Intangible assets acquired			32	30
Purchase price allocation adjustment				23
Amortization expense				$ 2
Residential mortgages | Franklin American Mortgage Company
Business Acquisition [Line Items]
MSR portfolio fair value			$ 590
Subsequent Event | Accounting Standards Update 2016-02
Business Acquisition [Line Items]
Right-of-use asset		$ 750
Lease liability		750
Subsequent Event | Accounting Standards Update 2017-12
Business Acquisition [Line Items]
Transfer of securities		755
Unrealized loss on transfer of securities		$ 15

[1] Adjustments to goodwill are the result of an update to the purchase price allocation for the FAMC acquisition, given higher value attributed to purchased net assets.