Acquisition (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended								8 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Revenues	$ 4,531	$ 4,264	$ 4,020	$ 3,609	$ 3,669	$ 3,511	$ 3,577	$ 3,500		$ 16,424	$ 14,257	$ 13,330
Net income (loss)	399	$ 490	$ 385	$ 367	816	$ 418	$ 411	$ 435		1,641	2,079	$ 1,192
Reinsurance recoverables	$ 17,748				$ 4,907				$ 17,748	$ 17,748	$ 4,907
Liberty Transaction [Member]
Business Acquisition [Line Items]
Acquisition agreement date										May 01, 2018
Capital stock acquired, percent	100.00%								100.00%	100.00%
Excess capital in LLAC (extraordinary dividend)										$ 1,800
Cash										1,500
Acquisition related costs										85
Provisional assets									$ (5)
Provisional liabilities									27
Provisional goodwill									32
Revenues									1,500
Net income (loss)									$ 36
Cash received from sale										$ 423