Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Cash Flows [Abstract]
Net cash flows provided by (used in) operating activities	$ 101	$ (14)
Fixed-maturity securities:
Purchases	(517)	(510)
Sales	155	183
Maturities	148	283
Net sales (purchases) of short-term investments	184	88
Proceeds from paydowns on financial guaranty variable interest entities’ assets	286	138
Other	19	55
Net cash flows provided by (used in) investing activities	275	237
Financing activities
Dividends paid	(20)	(19)
Repurchases of common stock	(35)	(39)
Share activity under option and incentive plans	0	(2)
Paydowns of financial guaranty variable interest entities’ liabilities	(281)	(167)
Repayment of long-term debt	(6)	(6)
Net cash flows provided by (used in) financing activities	(342)	(233)
Effect of exchange rate changes	1	(3)
Increase (decrease) in cash	35	(13)
Cash at beginning of period	184	138
Cash at end of period	219	125
Cash paid (received) during the period for:
Income taxes	37	32
Interest	$ 8	$ 9