Fair Value Of Financial Instruments (Aggregate Fair Value And Remaining Contractual Principal Balance Outstanding On Fair Value Option) (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
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	$ 40	$ 40
Loans receivable and other instruments, 90 days or more past due, contractual outstanding principal	144	141
Loans receivable and other instruments, fair value	40	40
Loans receivable and other instruments, 90 days or more past due, fair value	28	37
Loans receivable and other instruments, difference	0	0
Loans receivable and other instruments, 90 days or more past due, difference	116	104
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	184	181
Loans receivable and other instruments, fair value	68	77
Loans receivable and other instruments, difference	116	104
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	832	922
Long-term debt instruments, fair value	217	291
Long-term debt instruments, difference	615	631
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	52	108
Long-term debt instruments, fair value	42	98
Long-term debt instruments, difference	$ 10	$ 10