Debt (Principal Payments For Investment Agreements, MTNs and VIE Obligations) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total expected principal payments		$ 2,585	$ 2,428
Investment Agreement Obligations [Member]
Debt Instrument [Line Items]
2024		23
2025		35
2026		59
2027		29
2028		29
Thereafter		63
Total expected principal payments	[1]	238
Less discount and other adjustments	[2]	17
Total		221
Accrued interest		4
Carrying amount adjustment		$ 2
Latest maturity year		2037
Medium-term notes [Member]
Debt Instrument [Line Items]
2024		$ 34
2025		32
2026		0
2027		2
2028		30
Thereafter		572
Total expected principal payments	[3]	670
Less discount and other adjustments	[4]	173
Total		497
Accrued interest		3
Carrying amount adjustment		$ 12
Latest maturity year		2035
Variable Interest Entity Debt [Member] | International And Structured Finance Insurance [Member]
Debt Instrument [Line Items]
Latest maturity year		2038
Variable Interest Entity Debt [Member] | MBIA insured Variable Interest Entity [Member]
Debt Instrument [Line Items]
2024		$ 43
2025		9
2026		8
2027		4
2028		5
Thereafter		27
Total expected principal payments		$ 96

[1] Amounts reflect principal due at maturity for investment agreements issued at a discount.

[2] Discount is net of carrying amount adjustment of $2 million and accrued interest adjustment of $4 million.

[3] Amounts reflect principal due at maturity for notes issued at a discount.

[4] Discount is net of carrying amount and market value adjustments of $12 million and accrued interest adjustment of $3 million.