BASIS OF PRESENTATION Operating Leases (Details) - USD ($) $ in Millions	Aug. 01, 2018	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Operating Leased Assets [Line Items]
Goodwill			$ 6,946	$ 6,887
Accounting Standards Update 2016-02 | Scenario, Forecast | Minimum
Operating Leased Assets [Line Items]
Right of use asset		$ 600
Operating lease liability		600
Accounting Standards Update 2016-02 | Scenario, Forecast | Maximum
Operating Leased Assets [Line Items]
Right of use asset		750
Operating lease liability		$ 750
Franklin American Mortgage Company
Operating Leased Assets [Line Items]
Consideration transferred	$ 582
Goodwill	59
Intangible assets acquired	32
Residential mortgages | Franklin American Mortgage Company
Operating Leased Assets [Line Items]
MSR portfolio fair value	$ 590