Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended			6 Months Ended	9 Months Ended
	Oct. 17, 2022	Oct. 10, 2022	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Equity [Line Items]
Common stock, shares authorized (in shares)			4,000,000,000				4,000,000,000		4,000,000,000
Authorized shares of nonvoting common shares (in shares)			200,000,000				200,000,000		200,000,000
Common stock, par value (in dollars per share)			$ 0.01				$ 0.01		$ 0.01
Nonvoting common stock, par value (in dollars per share)			0.01				$ 0.01		$ 0.01
Shares remitted by employees to satisfy minimum statutory employee tax withholding (in shares)							11,644
Total value of shares remitted							$ 4
Amount of share-based awards cancelled to satisfy minimum statutory employee tax withholding requirements (in shares)							4,600,000
Value of share-based awards cancelled to satisfy minimum statutory employee tax withholding requirements							$ 1,590
Dividends declared per common share (in dollars per share)			$ 2.50		$ 2.00		$ 6.50	$ 4.50
Redemption value			$ 10,703				$ 10,703
Date of dividends declared on preferred shares							Oct. 10, 2022
GreenSky, Inc
Equity [Line Items]
Number of shares issued (in shares)				5,500,000
Number of shares issue or issuable subject to future service (in shares)				325,000
Subsequent Event
Equity [Line Items]
Dividends declared per common share (in dollars per share)	$ 2.50
Series N Preferred Stock
Equity [Line Items]
Dividend rate						6.30%
Redemption value						$ 675
Redemption price per share (in dollars per share)						$ 25,000
Preferred stock dividends declared (in dollars per share)							$ 0	787.50
Series M Preferred Stock
Equity [Line Items]
Dividend rate						5.375%
Redemption value						$ 2,000
Redemption price per share (in dollars per share)						$ 25,000
Difference between the redemption value of Preferred Stock and the net carrying value at the time of redemption						$ 41
Series A Preferred Stock
Equity [Line Items]
Redemption value			$ 750				$ 750
Preferred stock dividends declared (in dollars per share)			$ 239.58		239.58		$ 710.93	710.93
Series A Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		$ 239.58
Series C Preferred Stock
Equity [Line Items]
Redemption value			$ 200				$ 200
Preferred stock dividends declared (in dollars per share)			$ 255.56		255.56		$ 758.34	758.34
Series C Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		255.56
Series D Preferred Stock
Equity [Line Items]
Redemption value			$ 1,350				$ 1,350
Preferred stock dividends declared (in dollars per share)			$ 255.56		255.56		$ 758.34	758.34
Series D Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		255.56
Series J Preferred Stock
Equity [Line Items]
Redemption value			$ 1,000				$ 1,000
Preferred stock dividends declared (in dollars per share)			$ 343.75		343.75		$ 1,031.25	1,031.25
Series J Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		343.75
Series K Preferred Stock
Equity [Line Items]
Redemption value			$ 700				$ 700
Preferred stock dividends declared (in dollars per share)			$ 398.44		398.44		$ 1,195.32	1,195.32
Series K Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		398.44
Series Q Preferred Stock
Equity [Line Items]
Redemption value			$ 500				$ 500
Preferred stock dividends declared (in dollars per share)			$ 687.50		687.50		$ 1,375	1,375
Series R Preferred Stock
Equity [Line Items]
Redemption value			$ 600				$ 600
Preferred stock dividends declared (in dollars per share)			$ 618.75		618.75		$ 1,237.5	1,237.5
Series S Preferred Stock
Equity [Line Items]
Redemption value			$ 350				$ 350
Preferred stock dividends declared (in dollars per share)			$ 550.00		550.00		$ 1,100	1,100
Series U Preferred Stock
Equity [Line Items]
Redemption value			$ 750				$ 750
Preferred stock dividends declared (in dollars per share)			$ 456.25		0		$ 942.92	0
Series E Preferred Stock
Equity [Line Items]
Redemption value			$ 767				$ 767
Preferred stock dividends declared (in dollars per share)			$ 1,022.22		1,022.22		$ 3,044.44	3,044.44
Series E Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		1,011.11
Series F Preferred Stock
Equity [Line Items]
Redemption value			$ 161				$ 161
Preferred stock dividends declared (in dollars per share)			$ 1,022.22		$ 1,022.22		$ 3,044.44	3,044.44
Series F Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		1,011.11
Series O Preferred Stock
Equity [Line Items]
Redemption value			$ 650				$ 650
Preferred stock dividends declared (in dollars per share)							$ 662.50	662.50
Series O Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		662.50
Series P Preferred Stock
Equity [Line Items]
Redemption value			1,500				$ 1,500
Preferred stock dividends declared (in dollars per share)							$ 625.00	625.00
Series P Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		625.00
Series T Preferred Stock
Equity [Line Items]
Redemption value			675				$ 675
Preferred stock dividends declared (in dollars per share)							$ 475.00	0
Series T Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		475.00
Series V Preferred Stock
Equity [Line Items]
Redemption value			$ 750				$ 750
Preferred stock dividends declared (in dollars per share)							$ 547.14	$ 0
Series V Preferred Stock | Subsequent Event | Group Inc.
Equity [Line Items]
Preferred stock dividends declared (in dollars per share)		$ 515.63