Consolidated Variable Interest Entities - Effect of Consolidating FG VIE's on Financial Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Variable Interest Entity [Line Items]
Net earned premiums	$ 136	$ 162	$ 281	$ 326
Net investment income	99	101	200	223
Fair value gains (losses) on FG VIEs	2	12	6	22
Loss and LAE	44	72	26	131
Income (loss) before income taxes	87	150	304	522
Less: tax provision (benefit)	12	(3)	32	52
Net income (loss)	75	153	272	470
Effect on OCI	4	0	2	0
Net cash flows provided by (used in) operating activities			444	198
Effect on shareholders' equity (decrease) increase	6,634		6,634		$ 6,839
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Net earned premiums	(3)	(4)	(6)	(8)
Net investment income	(1)	(1)	(2)	(2)
Fair value gains (losses) on FG VIEs	2	12	6	22
Loss and LAE	(3)	2	3	4
Income (loss) before income taxes	(5)	9	1	16
Less: tax provision (benefit)	(1)	3	0	6
Net income (loss)	(4)	6	1	10
Effect on OCI	4	0	2	0
Net cash flows provided by (used in) operating activities	4	$ 5	6	$ 10
Effect on shareholders' equity (decrease) increase	$ 5		$ 5		$ 2