Consolidated Statements of Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Net earned premiums	$ 690	$ 864	$ 766
Net investment income	418	408	423
Net realized investment gains (losses):
Other-than-temporary impairment losses	(33)	(47)	(47)
Less: portion of other-than-temporary impairment loss recognized in other comprehensive income	10	4	0
Net impairment loss	(43)	(51)	(47)
Other net realized investment gains (losses)	83	22	21
Net realized investment gains (losses)	40	(29)	(26)
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	(10)	29	(18)
Net unrealized gains (losses)	121	69	746
Net change in fair value of credit derivatives	111	98	728
Fair value gains (losses) on committed capital securities	(2)	0	27
Fair value gains (losses) on financial guaranty variable interest entities	30	38	38
Bargain purchase gain and settlement of pre-existing relationships, net	58	259	214
Other income (loss)	394	39	37
Total revenues	1,739	1,677	2,207
Expenses
Loss and loss adjustment expenses	388	295	424
Amortization of deferred acquisition costs	19	18	20
Interest expense	97	102	101
Other operating expenses	244	245	231
Total expenses	748	660	776
Income (loss) before income taxes	991	1,017	1,431
Provision (benefit) for income taxes
Current	11	117	75
Deferred	250	19	300
Total provision (benefit) for income taxes	261	136	375
Net income (loss)	$ 730	$ 881	$ 1,056
Earnings per share:
Basic (in dollars per share)	$ 6.05	$ 6.61	$ 7.12
Diluted (in dollars per share)	5.96	6.56	7.08
Dividends (in dollars per share)	$ 0.57	$ 0.52	$ 0.48