Condensed Financial Information of The Registrant (Details) - USD ($)		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	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2006
Assets
Fixed maturity securities available-for-sale													$ 56,735,000,000	$ 51,121,000,000
Short-term investments													227,000,000	64,000,000
Cash and cash equivalents		$ 3,408,000,000			$ 1,449,000,000	$ 1,449,000,000			$ 1,890,000,000	$ 3,408,000,000	$ 1,890,000,000	$ 1,304,000,000	3,408,000,000	1,449,000,000	$ 1,890,000,000	$ 1,304,000,000
Other assets													896,000,000	878,000,000
Total assets													84,656,000,000	76,731,000,000
Liabilities and Stockholders’ Equity
Other liabilities													1,340,000,000	1,188,000,000
Total stockholders equity													14,352,000,000	11,601,000,000	8,450,000,000	9,570,000,000
Total liabilities and stockholders’ equity													84,656,000,000	76,731,000,000
CONSOLIDATED STATEMENTS OF INCOME
Total investment related gains (losses), net										(33,000,000)	91,000,000	(170,000,000)
Provision for income taxes										138,000,000	262,000,000	130,000,000
Net Income (Loss) Attributable to Parent		132,000,000	$ 213,000,000	$ 158,000,000	(88,000,000)	235,000,000	$ 263,000,000	$ 202,000,000	170,000,000	415,000,000	870,000,000	716,000,000
Other Comprehensive Income (Loss), Net of Tax										2,222,000,000	2,501,000,000	(1,424,000,000)
Total comprehensive income (loss)										2,637,000,000	3,371,000,000	(708,000,000)
Debt Disclosure [Abstract]
Debt Issuance Cost													(24,000,000)	(22,000,000)
Long-term Debt, Gross													3,597,000,000	3,003,000,000
Debt Instrument, Face Amount																	$ 850,000,000
Cash flows from operating activities
Net Income (Loss) Attributable to Parent		132,000,000	$ 213,000,000	$ 158,000,000	(88,000,000)	235,000,000	$ 263,000,000	$ 202,000,000	170,000,000	415,000,000	870,000,000	716,000,000
Other, net										(98,000,000)	(57,000,000)	(2,000,000)
Net cash provided by operating activities										3,322,000,000	2,307,000,000	1,581,000,000
Cash flows from investing activities
Sales of fixed maturity securities available-for-sale										6,514,000,000	13,214,000,000	9,340,000,000
Payments to Acquire Businesses, Net of Cash Acquired										0	4,000,000	(32,000,000)
Payments for (Proceeds from) Short-term Investments										(155,000,000)	199,000,000	129,000,000
Payments for (Proceeds from) Other Investing Activities										(335,000,000)	(304,000,000)	(365,000,000)
Net cash used in investing activities										(2,680,000,000)	(2,638,000,000)	(637,000,000)
Cash flows from financing activities
Dividends to stockholders										(182,000,000)	(163,000,000)	(140,000,000)
Purchases of treasury stock										(163,000,000)	(101,000,000)	(300,000,000)
Exercise of stock options, net										1,000,000	6,000,000	3,000,000
Maturities of Senior Debt										3,000,000	403,000,000	3,000,000
Proceeds from affiliated long-term debt issuance										(598,000,000)	(599,000,000)	0
Payments Of Debt Issuance Costs										(5,000,000)	(5,000,000)	0
Net cash used in financing activities										1,254,000,000	(121,000,000)	(322,000,000)
Cash and cash equivalents, beginning of period					1,449,000,000				1,890,000,000	1,449,000,000	1,890,000,000	1,304,000,000
Cash and cash equivalents, end of period		3,408,000,000				1,449,000,000				3,408,000,000	1,449,000,000	1,890,000,000
Supplementary information:
Income taxes paid, net of refunds										108,000,000	44,000,000	142,000,000
Cash Acquired from Acquisition											27,000,000	5,000,000
Long-term debt													3,573,000,000	2,981,000,000
Proceeds from Issuance of Common Stock										481,000,000	0	0
Parent Company [Member]
Assets
Fixed maturity securities available-for-sale													642,000,000	525,000,000
Short-term investments													172,000,000	19,000,000
Cash and cash equivalents		494,000,000			10,000,000	10,000,000			21,000,000	10,000,000	21,000,000	15,000,000	494,000,000	10,000,000	$ 21,000,000	$ 15,000,000
Investments In Subsidiary													16,937,000,000	14,486,000,000
Loans and Leases Receivable, Related Parties													1,010,000,000	1,010,000,000
Other assets													326,000,000	270,000,000
Total assets													19,581,000,000	16,320,000,000
Liabilities and Stockholders’ Equity
Long-term debt - affiliated	[1]												500,000,000	500,000,000
Other liabilities													1,160,000,000	1,244,000,000
Total stockholders equity													14,352,000,000	11,602,000,000
Total liabilities and stockholders’ equity													19,581,000,000	16,320,000,000
CONSOLIDATED STATEMENTS OF INCOME
Interest and Dividend Income, Operating	[2]									472,000,000	308,000,000	576,000,000
Total investment related gains (losses), net										14,000,000	4,000,000	(5,000,000)
Operating Expenses										(59,000,000)	(55,000,000)	(36,000,000)
Interest and Debt Expense										(202,000,000)	(206,000,000)	(181,000,000)
Income (loss) before income tax and undistributed earnings of subsidiaries										225,000,000	51,000,000	354,000,000
Provision for income taxes										(21,000,000)	(33,000,000)	(37,000,000)
Net income (loss) before undistributed earnings of subsidiaries										246,000,000	84,000,000	391,000,000
Equity In Undistributed Earnings Of Subsidiaries										169,000,000	786,000,000	325,000,000
Net Income (Loss) Attributable to Parent										415,000,000	870,000,000	716,000,000
Other Comprehensive Income (Loss), Net of Tax										(29,000,000)	(33,000,000)	21,000,000
Total comprehensive income (loss)										386,000,000	837,000,000	737,000,000
Debt Disclosure [Abstract]
Debt Issuance Cost													(25,000,000)	(22,000,000)
Proceeds from Dividends Received										340,000,000	175,000,000
Long-term Debt, Gross													3,594,000,000	2,996,000,000
Long-term Debt													500,000,000	500,000,000
Cash flows from operating activities
Net Income (Loss) Attributable to Parent										415,000,000	870,000,000	716,000,000
Equity Net Earnings Subsidiaries										(169,000,000)	(786,000,000)	(325,000,000)
Other, net										(170,000,000)	72,000,000	37,000,000
Net cash provided by operating activities										76,000,000	156,000,000	428,000,000
Cash flows from investing activities
Sales of fixed maturity securities available-for-sale										358,000,000	576,000,000	482,000,000
Purchases of fixed maturity securities available-for-sale										(400,000,000)	(494,000,000)	(383,000,000)
Payments for (Proceeds from) Short-term Investments										(165,000,000)	0	0
Payments for (Proceeds from) Other Investing Activities										(26,000,000)	0	0
Capital Contributions To Subsidiaries										(78,000,000)	(96,000,000)	(82,000,000)
Net cash used in investing activities										(311,000,000)	(14,000,000)	17,000,000
Cash flows from financing activities
Dividends to stockholders										(182,000,000)	(163,000,000)	(140,000,000)
Purchases of treasury stock										(163,000,000)	(101,000,000)	(300,000,000)
Exercise of stock options, net										1,000,000	6,000,000	3,000,000
Net Change In Cash Collateral For Loaned Securities										(11,000,000)	(92,000,000)	(2,000,000)
Maturities of Senior Debt										0	(397,000,000)	0
Proceeds from affiliated long-term debt issuance										(598,000,000)	(599,000,000)	0
Payments Of Debt Issuance Costs										(5,000,000)	(5,000,000)	0
Net cash used in financing activities										719,000,000	(153,000,000)	(439,000,000)
Change in cash and cash equivalents										484,000,000	(11,000,000)	6,000,000
Cash and cash equivalents, beginning of period					$ 10,000,000				$ 21,000,000	10,000,000	21,000,000	15,000,000
Cash and cash equivalents, end of period		$ 494,000,000				$ 10,000,000				494,000,000	10,000,000	21,000,000
Supplementary information:
Interest paid										187,000,000	192,000,000	176,000,000
Income taxes paid, net of refunds										23,000,000	9,000,000	93,000,000
Long-term debt	[3]												3,569,000,000	2,974,000,000
Proceeds from Issuance of Common Stock										$ 481,000,000	$ 0	$ 0
Senior Notes Due 2019 [Member]
Debt Disclosure [Abstract]
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													6.45%
Senior Notes Due 2021 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													5.00%
Senior Notes Due 2021 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Senior Notes Due 2023 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													399,000,000	399,000,000
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													4.70%
Senior Notes Due 2023 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 399,000,000	399,000,000
Senior Notes Due 2026 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													400,000,000	400,000,000
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													3.95%
Senior Notes Due 2026 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Senior Notes Due 2029 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													599,000,000	599,000,000
Debt Instrument, Face Amount													$ 600,000,000
Debt Instrument, Interest Rate, Stated Percentage													3.90%
Senior Notes Due 2029 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 599,000,000	599,000,000
Subordinated Debentures Due 2042 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													400,000,000	400,000,000
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													6.20%
Subordinated Debentures Due 2042 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Subordinated Debentures Due 2056 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													400,000,000	400,000,000
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													5.75%
Subordinated Debentures Due 2056 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 400,000,000	400,000,000
Junior Subordinated Debentures Due 2065 [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													319,000,000	319,000,000
Debt Instrument, Face Amount													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage													4.82%
Junior Subordinated Debentures Due 2065 [Member] | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 398,000,000	398,000,000
Senior Notes Due 2030
Debt Disclosure [Abstract]
Long-term Debt, Gross													597,000,000	0
Debt Instrument, Face Amount													$ 600,000,000
Debt Instrument, Interest Rate, Stated Percentage													3.15%
Senior Notes Due 2030 | Parent Company [Member]
Debt Disclosure [Abstract]
Long-term Debt, Gross													$ 598,000,000	$ 0

[1] Long-term debt – affiliated in 2020 and 2019 consists of $500 million of subordinated debt issued to various operating subsidiaries.

[2] Interest/dividend income includes $340 million and $175 million of cash dividends received from consolidated subsidiaries in 2020 and 2019, respectively.

[3] Long-term debt – unaffiliated consists of the following: 20202019 $400 million 5.00% Senior Notes due 2021 $400 $400  $400 million 4.70% Senior Notes due 2023 399 399  $400 million 3.95% Senior Notes due 2026 400 400  $600 million 3.90% Senior Notes due 2029 599 599  $600 million 3.15% Senior Notes due 2030 598 —  $400 million 6.20% Subordinated Debentures due 2042 400 400  $400 million 5.75% Subordinated Debentures due 2056 400 400  $400 million Variable Rate Junior Subordinated Debentures due 2065 398 398 Subtotal3,594 2,996 Unamortized debt issuance costs(25)(22)Total$3,569 $2,974