Unsecured Borrowings - Unsecured Long-Term Borrowings after Hedging (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Fixed-rate obligations: At fair value	$ 5,692	$ 4,863
Fixed-rate obligations: At amortized cost	5,411	30,370
Floating-rate obligations: At fair value	59,666	47,527
Floating-rate obligations: At amortized cost	169,196	171,332
Total	$ 239,965	$ 254,092
Effective weighted average interest rates for unsecured long-term borrowings, after hedging - total	3.80%	1.60%
Effective weighted average interest rates for unsecured long-term borrowings, after hedging fixed rate obligations	4.30%	2.25%
Effective weighted average interest rates for unsecured long-term borrowings, after hedging floating rate obligations	3.78%	1.48%