Income Tax (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets, Valuation Allowance	$ 309	$ 294		$ 309	$ 294
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Policyholder Liabilities	3,890	3,635		3,890	3,635
Deferred Tax Assets, Other	0	127		0	127
Deferred Tax Liabilities, Investments	4,421	4,170		4,421	4,170
Deferred Tax Liabilities, Other	134	0		134	0
Deferred Tax Assets, Operating Loss Carryforwards	301	240		301	240
Provision for income tax expense (benefit)				1,509	886	$ 1,179
Operating Expenses				13,150	13,689	13,714
Tax Credit Carryforward, Amount	922	1,296		922	1,296
Deferred Federal Income Tax Expense (Benefit)				(115)	(235)	342
Settlement with Taxing Authority
Tax Adjustments, Settlements, and Unusual Provisions		(226)	$ (349)
Provision for income tax expense (benefit)		(158)	(168)
Operating Expenses	28	86	229
Operating Expenses Net	22	68	$ 181
Certain State and Foreign Net Operating Loss Carryforwards
Valuation allowance, change during year				301
Impact of U.S. Tax Reform
Provision for income tax expense (benefit)					(326)	66
Deferred Federal Income Tax Expense (Benefit)					(9)	(402)
Impact of U.S. Tax Reform | GILTI [Member]
Effective Income Tax Rate Reconciliation, Tax Contingency, Foreign, Amount				43	12
Provision for income tax expense (benefit)					35	$ 45
Other Assets
Deferred Tax Assets, Net	$ 94	$ 65		$ 94	$ 65