SHAREHOLDERS' EQUITY - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended								9 Months Ended
		Sep. 30, 2020		Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020		Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) or benefit		$ 1,303				$ (259)				$ 884		$ (865)
Net of tax		$ 2,456		$ 805	$ 566	$ 777		$ 817	$ 928	$ 3,826		$ 2,523
Blended statutory income tax rate		(112.90%)				25.00%				(30.00%)		25.50%
U.S. federal statutory income tax rate		21.00%								21.00%
Net investment gains (losses)		$ (13)				$ 41				$ 132		$ (1)
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax		3				(35)				(121)		(8)
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]
Income tax (expense) or benefit		(6)	[1]			10	[2]			28	[3]	0	[4]
Net of tax		7				(31)				(104)		1
Net investment gains (losses)		13				(41)				(132)		1
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)	[5]	(7)				(5)				(22)		(12)
Acquisition and operating expenses, prior service (cost) credit	[5]	0				0				0		0
Income tax (expense) or benefit		3	[1]			1	[2]			5	[3]	3	[4]
Net of tax		$ (4)				$ (4)				$ (17)		$ (9)

[1] Based on 21% tax rate, with a cumulative adjustment to the first six months of 2020 due to the effects of Final and Proposed Regulations released on September 29, 2020. See Note 9 of the Notes to the Consolidated Financial Statements.

[2] Based on 25% blended tax rate

[3] Based on 21% tax rate

[4] Based on 26% blended tax rate

[5] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 12 for additional details).