Condensed Consolidated Statements of Cash Flows (unaudited) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Statement of Cash Flows [Abstract]
Net cash flows provided by (used in) operating activities	$ (164)	$ (332)
Fixed-maturity securities:
Purchases	(278)	(196)
Sales	86	471
Maturities and paydowns	217	177
Short-term investments with maturities of over three months:
Purchases	(56)	(107)
Sales	4	2
Maturities and paydowns	12	67
Net sales (purchases) of short-term investments with original maturities of less than three months	375	25
Net proceeds from paydowns on financial guaranty variable interest entities’ assets	37	26
Proceeds from sales of other invested assets	1	27
Other	(9)	0
Net cash flows provided by (used in) investing activities	389	492
Financing activities
Dividends paid	(20)	(20)
Repurchases of common stock	(116)	(80)
Net paydowns of financial guaranty variable interest entities’ liabilities	(35)	(25)
Paydown of long-term debt	(21)	(3)
Other	(11)	(14)
Contributions from noncontrolling interests to investment vehicles	23	0
Net cash flows provided by (used in) financing activities	(180)	(142)
Effect of foreign exchange rate changes	(7)	1
Increase (decrease) in cash and restricted cash	38	19
Cash and restricted cash at beginning of period	183	104
Cash and restricted cash at end of period	221	123
Supplemental cash flow information
Interest on long-term debt	9	9
Purchases of fixed-maturity investments	0	(139)
Cash	139	123
Cash of Consolidated Investment Vehicles	$ 82	$ 0