Fair Value Of Financial Instruments (Aggregate Fair Value And Remaining Contractual Principal Balance Outstanding On Fair Value Option) (Detail) - USD ($) $ in Millions	Mar. 31, 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	$ 42	$ 39
Loans receivable and other instruments, 90 days or more past due, contractual outstanding principal	161	149
Loans receivable and other instruments, fair value	42	39
Loans receivable and other instruments, 90 days or more past due, fair value	41	39
Loans receivable and other instruments, difference	0	0
Loans receivable and other instruments, 90 days or more past due, difference	120	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	203	188
Loans receivable and other instruments, fair value	83	78
Loans receivable and other instruments, difference	120	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	610	780
Long-term debt instruments, fair value	154	172
Long-term debt instruments, difference	456	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	54	53
Long-term debt instruments, fair value	42	41
Long-term debt instruments, difference	$ 12	$ 12