SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Sales and redemptions		$ 91	$ 68
Other than temporary impairment losses realized	[1]	(14)	(6)
Total before tax		1,117	1,013
Income tax (expense) or benefit		(386)	(350)
Net of tax		$ 731	$ 663
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		$ 50	$ 32
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		91	56
Other than temporary impairment losses realized		(14)	(6)
Total before tax		77	50
Income tax (expense) or benefit	[2]	(27)	(18)
Net of tax		50	32
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]	(3)	(4)
Acquisition and operating expenses, prior service (cost) credit	[3]	3	4
Income tax (expense) or benefit	[2]	0	0
Net of tax		$ 0	$ 0

[1] Includes $14 and $6 for the three-month periods ended March 31, 2016 and 2015, respectively, from change in intent to sell securities

[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).