Fair Value Of Financial Instruments (Aggregate Fair Value And Remaining Contractual Principal Balance Outstanding On Fair Value Option) (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
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	$ 43	$ 39
Loans receivable and other instruments, 90 days or more past due, contractual outstanding principal	167	149
Loans receivable and other instruments, fair value	43	39
Loans receivable and other instruments, 90 days or more past due, fair value	27	39
Loans receivable and other instruments, difference	0	0
Loans receivable and other instruments, 90 days or more past due, difference	140	110
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	210	188
Loans receivable and other instruments, fair value	70	78
Loans receivable and other instruments, difference	140	110
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	503	780
Long-term debt instruments, fair value	183	172
Long-term debt instruments, difference	320	608
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	55	53
Long-term debt instruments, fair value	38	41
Long-term debt instruments, difference	$ 17	$ 12