SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Statements Of Cash Flows) (Details) - USD ($) $ in Millions		3 Months Ended										12 Months Ended
		Dec. 31, 2017		Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net income (loss)		$ 816	[1]	$ 418	$ 411	$ 435	$ 189	[1]	$ 467	$ 325	$ 211	$ 2,079	$ 1,192	$ 1,154
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Other												213	278	109
Net cash provided by (used in) operating activities												788	1,272	2,243
Cash Flows from Investing Activities
Net change in collateral on investments and derivatives												(429)	415	578
Net cash provided by (used in) investing activities												(4,188)	(3,666)	(4,223)
Cash Flows from Financing Activities
Payment of long-term debt, including current maturities													(600)	(250)
Issuance of long-term debt, net of issuance costs													395	298
Payment related to early extinguishment of debt													(59)
Repurchase of common stock												(725)	(879)	(900)
Dividends paid to common stockholders												(262)	(238)	(204)
Net cash provided by (used in) financing activities												2,306	1,970	1,207
Net increase (decrease) in cash and invested cash												(1,094)	(424)	(773)
Cash and invested cash as of beginning-of-year						2,722					3,146	2,722	3,146	3,919
Cash and invested cash as of end-of-year		1,628					2,722					1,628	2,722	3,146
Parent Company [Member]
Cash Flows from Operating Activities
Net income (loss)												2,079	1,192	1,154
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Equity in (income) loss of subsidiaries greater than distributions	[2]											(1,166)	(325)	(92)
Realized (gain) loss												3
Change in federal income tax accruals												107	120	106
Other												20	54	(74)
Net cash provided by (used in) operating activities												1,043	1,041	1,094
Cash Flows from Investing Activities
Net change in collateral on investments and derivatives												3
Capital contribution to subsidiaries	[2]											(60)		(75)
Increase (decrease) in collateral on investments												(45)	(23)	(38)
Net cash provided by (used in) investing activities												(102)	(23)	(113)
Cash Flows from Financing Activities
Payment of long-term debt, including current maturities													(350)	(250)
Issuance of long-term debt, net of issuance costs													395	300
Payment related to early extinguishment of debt													(59)
Increase (decrease) in loans from subsidiaries, net	[2]											(230)	37	68
Increase (decrease) in loans to subsidiaries, net	[2]											239	(20)	(27)
Common stock issued for benefit plans and excess tax benefits												46	26	47
Repurchase of common stock												(725)	(879)	(900)
Dividends paid to common stockholders												(262)	(238)	(204)
Net cash provided by (used in) financing activities												(932)	(1,088)	(966)
Net increase (decrease) in cash and invested cash												9	(70)	15
Cash and invested cash as of beginning-of-year						$ 611					$ 681	611	681	666
Cash and invested cash as of end-of-year		$ 620					$ 611					$ 620	$ 611	$ 681

[1] Fourth quarter 2017 results include a goodwill impairment charge and the impacts of remeasuring our existing deferred tax balances for the impact of the Tax Act as disclosed elsewhere herein

[2] Eliminated in consolidation.