Shareholders' Equity - Summary of Preferred Dividends Declared on Preferred Stock Issued (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Class of Stock [Line Items]
Total preferred stock dividends declared	$ 238	$ 192	$ 643	$ 529
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 335.68	$ 413.68	$ 1,016.67	$ 1,215.99
Total preferred stock dividends declared	$ 9	$ 12	$ 30	$ 36
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 335.68	$ 413.68	$ 1,016.67	$ 1,215.99
Total preferred stock dividends declared	$ 2	$ 4	$ 8	$ 10
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 330.63	$ 408.45	$ 1,001.56	$ 1,200.65
Total preferred stock dividends declared	$ 18	$ 22	$ 54	$ 65
Series E Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 1,369.51	$ 1,629.22	$ 4,118.75	$ 4,911.94
Total preferred stock dividends declared	$ 11	$ 13	$ 32	$ 38
Series F Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 1,370.15	$ 1,629.85	$ 4,120.64	$ 4,913.85
Total preferred stock dividends declared	$ 3	$ 3	$ 7	$ 8
Series K Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 0	$ 796.88
Total preferred stock dividends declared			$ 0	$ 20
Series O Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 662.50	$ 662.50
Total preferred stock dividends declared			$ 17	$ 17
Series P Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 0	$ 552.33	$ 0	$ 1,623.09
Total preferred stock dividends declared	$ 0	$ 33	$ 0	$ 97
Series Q Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 922.38	$ 687.50	$ 1,844.75	$ 1,375
Total preferred stock dividends declared	$ 19	$ 14	$ 37	$ 28
Series R Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 945.00	$ 618.75	$ 1,563.75	$ 1,237.5
Total preferred stock dividends declared	$ 23	$ 15	$ 38	$ 30
Series S Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 898.25	$ 550.00	$ 1,448.25	$ 1,100
Total preferred stock dividends declared	$ 12	$ 7	$ 20	$ 15
Series T Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 475.00	$ 475.00
Total preferred stock dividends declared			$ 13	$ 13
Series U Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 456.25	$ 456.25	$ 912.50	$ 912.50
Total preferred stock dividends declared	$ 13	$ 13	$ 27	$ 27
Series V Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 515.63	$ 515.63
Total preferred stock dividends declared			$ 15	$ 15
Series W Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 937.50	$ 937.50	$ 1,875	$ 1,833.33
Total preferred stock dividends declared	$ 57	$ 56	$ 113	$ 110
Series X Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 937.50	$ 0
Total preferred stock dividends declared			$ 84	$ 0
Series Y Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)			$ 952.78	$ 0
Total preferred stock dividends declared			$ 77	$ 0
Series Z Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends declared (in dollars per share)	$ 932.36	$ 0	$ 932.36	$ 0
Total preferred stock dividends declared	$ 71	$ 0	$ 71	$ 0