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Fair Value of Financial Instruments (Aggregate Fair Value And Remaining Contractual Principal Balance Outstanding On Fair Value Option) (Detail) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Residential Mortgage Loans [Member] | Loans Receivable [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable and other instruments, contractual outstanding principal	$ 12	$ 12
Loans receivable and other instruments, 90 days or more past due, contractual outstanding principal	49	48
Loans receivable and other instruments, fair value	12	12
Loans receivable and other instruments, 90 days or more past due, fair value	18	16
Loans receivable and other instruments, difference	0	0
Loans receivable and other instruments, 90 days or more past due, difference	31	32
Corporate Loans - Current [Member] | Loans Receivable [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable and other instruments, contractual outstanding principal	17	16
Loans receivable and other instruments, fair value	14	15
Loans receivable and other instruments, difference	3	1
Total Loans Receivable and Other Instruments [Member] | Loans Receivable [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Loans receivable and other instruments, contractual outstanding principal	78	76
Loans receivable and other instruments, fair value	44	43
Loans receivable and other instruments, difference	34	33
Variable Interest Entity Notes [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Long-term debt instruments, contractual outstanding principal	40	45
Long-term debt instruments, fair value	27	31
Long-term debt instruments, difference	13	14
Medium Term Notes [Member]
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items]
Long-term debt instruments, contractual outstanding principal	54	52
Long-term debt instruments, fair value	37	35
Long-term debt instruments, difference	$ 17	$ 17

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- Definition

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- Definition

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+ References

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