Fair Value Hierarchy - Summary of Weighted Average of Significant Unobservable Inputs, Loans (Detail) $ in Millions	Sep. 30, 2023 USD ($) yr	Dec. 31, 2022 USD ($) yr
Loans at fair value | $	$ 6,448	$ 7,655
Level 3
Loans at fair value | $	972	1,837
Corporate
Loans at fair value | $	871	996
Corporate | Level 3
Loans at fair value | $	431	637
Real estate | Level 3
Loans at fair value | $	321	785
Other collateralized
Loans at fair value | $	850	716
Other collateralized | Level 3
Loans at fair value | $	142	140
Other
Loans at fair value | $	148	286
Other | Level 3
Loans at fair value | $	$ 78	$ 275
Minimum | Yield | Corporate | Level 3
Measurement input	0.088	0.041
Minimum | Yield | Real estate | Level 3
Measurement input	0.050	0.030
Minimum | Yield | Other collateralized | Level 3
Measurement input	0.066	0.058
Minimum | Yield | Other | Level 3
Measurement input	0.094	0.094
Minimum | Recovery rate | Corporate | Level 3
Measurement input	0.020	0.231
Minimum | Recovery rate | Real estate | Level 3
Measurement input	0.042	0.036
Minimum | Duration (years) | Corporate | Level 3
Measurement input	0.9	1.6
Minimum | Duration (years) | Real estate | Level 3
Measurement input	0.2	0.6
Minimum | Duration (years) | Other collateralized | Level 3
Measurement input	1.8	2.5
Minimum | Duration (years) | Other | Level 3
Measurement input	2.8
Maximum | Yield | Corporate | Level 3
Measurement input	0.128	0.269
Maximum | Yield | Real estate | Level 3
Measurement input	0.205	0.270
Maximum | Yield | Other collateralized | Level 3
Measurement input	0.209	0.127
Maximum | Yield | Other | Level 3
Measurement input	0.154	0.100
Maximum | Recovery rate | Corporate | Level 3
Measurement input	0.950	0.950
Maximum | Recovery rate | Real estate | Level 3
Measurement input	0.992	0.662
Maximum | Duration (years) | Corporate | Level 3
Measurement input	4.3	3.3
Maximum | Duration (years) | Real estate | Level 3
Measurement input	6.2	6.7
Maximum | Duration (years) | Other collateralized | Level 3
Measurement input	2.2	2.9
Maximum | Duration (years) | Other | Level 3
Measurement input	5.3
Weighted Average | Yield | Corporate | Level 3
Measurement input	0.093	0.096
Weighted Average | Yield | Real estate | Level 3
Measurement input	0.176	0.161
Weighted Average | Yield | Other collateralized | Level 3
Measurement input	0.098	0.077
Weighted Average | Yield | Other | Level 3
Measurement input	0.118	0.099
Weighted Average | Recovery rate | Corporate | Level 3
Measurement input	0.600	0.660
Weighted Average | Recovery rate | Real estate | Level 3
Measurement input	0.501	0.544
Weighted Average | Duration (years) | Corporate | Level 3
Measurement input	2.3	2.6
Weighted Average | Duration (years) | Real estate | Level 3
Measurement input	1.8	2.5
Weighted Average | Duration (years) | Other collateralized | Level 3
Measurement input	1.9	2.7
Weighted Average | Duration (years) | Other | Level 3
Measurement input	3.8