Other Comprehensive Income (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
Mar. 31, 2020	Mar. 31, 2020	Mar. 31, 2019
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period		$ 64,170	$ 58,543
Other comprehensive income (loss) before reclassifications, net of tax	$ (5)
Other comprehensive income (loss), net of tax		(332)	331
Balance at end of period	65,474	65,474	60,006
Net unrealized investment gains (losses)
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period		774	97
Other comprehensive income (loss) before reclassifications, net of tax		(394)	348
Amounts reclassified from accumulated other comprehensive loss, net of tax		83	(14)
Other comprehensive income (loss), net of tax		(311)	334
Balance at end of period	463	463	431
OCI before Reclass, pre-tax		(486)	410
Amounts reclassified, pre-tax		101	(19)
Foreign currency translation adjustments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period		4	(158)
Other comprehensive income (loss) before reclassifications, net of tax		(12)	1
Other comprehensive income (loss), net of tax		(12)	1
Balance at end of period	(8)	(8)	(157)
Net cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period		279	312
Other comprehensive income (loss) before reclassifications, net of tax		(5)	0
Amounts reclassified from accumulated other comprehensive loss, net of tax		(4)	(4)
Other comprehensive income (loss), net of tax		(9)	(4)
Balance at end of period	270	270	308
Amount expected to be reclassified	14	14
OCI before Reclass, pre-tax		(7)	0
Amounts reclassified, pre-tax		(6)	(5)
Pension and OPEB plans
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period		(38)	(149)
Other comprehensive income (loss), net of tax		0	0
Balance at end of period	(38)	(38)	(149)
AOCI Including Portion Attributable to Noncontrolling Interest
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period		1,019	102
Balance at end of period	$ 687	$ 687	$ 433

Changes In Accumulated Other Comprehensive Income (Loss) By Component [Roll Forward]

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The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

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Amount before tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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