SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and redemptions		$ (17)	$ 26	$ 87	$ 186
Other than temporary impairment losses realized	[1]	(22)	(137)	(69)	(143)
Total before tax		963	864	2,914	2,752
Income tax (expense) or benefit		(334)	(297)	(1,006)	(949)
Net of tax		$ 629	$ 567	$ 1,908	$ 1,803
The expected U.S. tax rate		35.00%	35.00%	35.00%	35.00%
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		$ (22)	$ (90)	$ 18	$ (14)
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		(11)	(1)	102	123
Other than temporary impairment losses realized		(22)	(137)	(69)	(143)
Total before tax		(33)	(138)	33	(20)
Income tax (expense) or benefit	[2]	12	48	(12)	7
Net of tax		(21)	(90)	21	(13)
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)	[3]	(4)	(4)	(12)	(13)
Acquisition and operating expenses, prior service (cost) credit	[3]	2	4	8	12
Income tax (expense) or benefit	[2]	1	0	1	0
Net of tax		$ (1)	$ 0	$ (3)	$ (1)

[1] Includes $22 and $6 for the three-month periods and $69 and $12 for the nine-month periods ended September 30, 2016 and 2015, respectively, from change in intent to sell securities or change in intent to hold securities until recovery; and $131 for the three- and nine-month periods ended September 30, 2015, for credit-related impairments

[2] Based on 35% tax rate

[3] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 10 for additional details).