Equity (Schedule of Reclassifications out of AOCI) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other investment related gains (losses), net										$ (12)	$ 122	$ (142)
Investment income, net of related expenses										2,575	2,520	2,139
Deferred Policy Acquisition Cost, Amortization Expense, Unrealized Investment Gains (Losses)										26	97	(27)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax										1	1	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax										2	23	(1)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		$ 169	$ 285	$ 195	$ (96)	$ 308	$ 347	$ 260	$ 217	553	1,132	846
Income Tax Expense (Benefit)										(138)	(262)	(130)
Net Income (Loss) Attributable to Parent		$ 132	$ 213	$ 158	$ (88)	$ 235	$ 263	$ 202	$ 170	415	870	$ 716
Amortization Of Unrealized Pension And Postretirement Benefits [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	[1]									1	(1)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	[1]									(7)	(5)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest										(6)	(4)
Income Tax Expense (Benefit)										1	1
Net Income (Loss) Attributable to Parent										(5)	(3)
Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other investment related gains (losses), net										(8)	84
Deferred Policy Acquisition Cost, Amortization Expense, Unrealized Investment Gains (Losses)	[2]									54	97
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest										42	182
Income Tax Expense (Benefit)										(12)	(38)
Net Income (Loss) Attributable to Parent										30	144
Amounts Reclassified From AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income (Loss) Attributable to Parent										25	141
Interest Rate Options [Member] | Unrealized Gains Losses On Available For Sale Securities [Member] | Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[3]									(4)	1
Currency Swap [Member] | Unrealized Gains Losses On Available For Sale Securities [Member] | Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[3]									0	0
Forward Contracts [Member] | Unrealized Gains Losses On Available For Sale Securities [Member] | Unrealized Appreciation Depreciation Of Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	[3]									$ 0	$ 0

[1] See Note 10 for information on employee benefit plans.

[2] See Note 8 for information on deferred policy acquisition costs.

[3] See Note 5 for information on cash flow hedges.