SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended						6 Months Ended
		Jun. 30, 2021		Mar. 31, 2021	Jun. 30, 2020		Mar. 31, 2020	Jun. 30, 2021		Jun. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)		$ (5)			$ 75			$ 15		$ 145
Net investment gains (losses)		1			(1)			1		(5)
Income tax (expense) or benefit		(268)			(265)			(579)		(419)
Net of tax		$ 1,105		$ 1,293	$ 805		$ 566	$ 2,398		$ 1,370
U.S. federal statutory income tax rate		21.00%						21.00%
Blended statutory income tax rate					25.00%					23.00%
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		$ (4)			$ (61)			$ (29)		$ (122)
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized gains (losses) on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)		5			(75)			(15)		(145)
Income tax (expense) or benefit		(1)	[1]		19	[2]		3	[1]	34	[3]
Net of tax		4			(56)			(12)		(111)
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized gains (losses) on derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)		(1)						(2)
Income tax (expense) or benefit	[1]	0						0
Net of tax		(1)						(2)
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)	[4]	(9)			(7)			(19)		(15)
Acquisition and operating expenses, prior service (cost) credit	[4]	0			0			0		0
Income tax (expense) or benefit		2	[1]		2	[2]		4	[1]	4	[3]
Net of tax		$ (7)			$ (5)			$ (15)		$ (11)

[1] Based on 21% tax rate

[2] Based on 25% blended tax rate

[3] Based on 23% blended tax rate

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