SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and redemptions		$ (7)	$ 91
Other than temporary impairment losses realized		(10)	(14)
Total before tax		898	1,117
Income tax (expense) or benefit		(306)	(386)
Net of tax		$ 592	$ 731
The expected U.S. tax rate		35.00%	35.00%
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		$ (12)	$ 50
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized gains (losses) on investment securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and redemptions		(6)	91
Other than temporary impairment losses realized		(10)	(14)
Total before tax		(16)	77
Income tax (expense) or benefit	[1]	6	(27)
Net of tax		(10)	50
Reclassification Out Of Accumulated Other Comprehensive Income | Pension liability adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Acquisition and operating expenses, actuarial gains (losses)	[2]	(3)	(3)
Acquisition and operating expenses, prior service (cost) credit	[2]	0	3
Income tax (expense) or benefit	[1]	1	0
Net of tax		$ (2)	$ 0

[1] Based on 35% tax rate

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 11 for additional details).