DISCONTINUED OPERATIONS AND SIGNIFICANT DISPOSALS - Significant Disposals (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 21, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pretax gain on sale	[1]		$ 247	$ 602
Mexico Asset Management Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net assets derecognized					$ 96
Goodwill					$ 32
Pretax gain on sale		$ 250
After-tax gain on sale		$ 150

[1] See Note 2 to the Consolidated Financial Statements for further information on significant disposals.