Commitments and Contingencies (Narrative) (Detail) $ in Millions	Mar. 31, 2025 USD ($) LegalProceedings
Commitments And Contingencies [Line Items]
Other material legal proceedings pending \| LegalProceedings	0
MBIA Corp [Member] \| Fully Drawn [Member]
Commitments And Contingencies [Line Items]
Other Commitment \| $	$ 15

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant