DISCONTINUED OPERATIONS AND SIGNIFICANT DISPOSALS - Significant Disposals (Details) loan in Thousands, $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($) employee branch loan	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Discontinued operations
Pre-tax gain (loss) on sale	[1]					$ 19	$ 422
Disposed of by sale, not discontinued operations | Novation of 80% Primerica Coinsurance Agreement
Discontinued operations
Coinsurance agreement percentage					80.00%
Pre-tax gain (loss) on sale					$ 404
After tax gain (loss) on sale of disposal group					263
AFS securities and cash					1,500
Deferred policy acquisition costs					950
Liabilities					$ 2,700
Disposed of by sale, not discontinued operations | US Mortgage Servicing Operations
Discontinued operations
Pre-tax gain (loss) on sale			$ (331)
After tax gain (loss) on sale of disposal group			(207)
Loss on disposal including other costs relating to disposal			382
Servicing related assets			1,162
Mortgage servicing rights			$ 1,046
Number of loans disposed of | loan			750
Loans, net			$ 93,000
Disposed of by sale, not discontinued operations | CitiFinancial Canada
Discontinued operations
Pre-tax gain (loss) on sale			350
After tax gain (loss) on sale of disposal group			178
Liabilities			1,500
Loans, net			$ 1,700
Number of branches | branch			220
Number of employees | employee			1,400
Assets			$ 1,900
Amount of debt settled			$ 400
Income before taxes		$ 0		$ 41		41	78
Disposal group, held-for-sale | Fixed Income Analytics and Index Businesses
Discontinued operations
Liabilities		0				0
Assets		100				100
Goodwill		72				72
Income before taxes		$ 9		$ 17		$ 19	$ 31

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