Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions							12 Months Ended
	Jun. 01, 2021	Mar. 30, 2021	Mar. 18, 2021	Dec. 11, 2020	Oct. 06, 2020	Apr. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 30, 2019
Class of Stock [Line Items]
Common stock, shares authorized (shares)							3,000,000,000	3,000,000,000
Preferred stock, aggregate liquidation preference							$ 10,100	$ 7,850
Preferred stock, par value (USD per share)							$ 0.01	$ 0.01
Shares repurchased (in shares)							0	0	55,000,000
Shares repurchased									$ 2,200
Preferred stock, shares authorized (in shares)							9,940,000	9,940,000
TD Ameritrade Holding [Member]
Class of Stock [Line Items]
Number of shares issued in acquisition (in shares)					586,000,000
Common Stock [Member]
Class of Stock [Line Items]
Number of shares issued (in shares)							0	0	0
Share repurchase, authorized amount										$ 4,000
Common Stock [Member] | TD Ameritrade Holding [Member]
Class of Stock [Line Items]
Number of shares issued in acquisition (in shares)					509,000,000
Common Stock [Member] | TD Ameritrade Holding [Member] | TD Bank [Member]
Class of Stock [Line Items]
Number of shares issued in acquisition (in shares)					177,000,000
Maximum percentage of voting interest					9.90%
Nonvoting Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized (shares)					300,000,000		300,000,000	300,000,000
Nonvoting Common Stock [Member] | TD Ameritrade Holding [Member] | TD Bank [Member]
Class of Stock [Line Items]
Number of shares issued in acquisition (in shares)					77,000,000
Shares converted (in shares)					2,000,000
Number of shares held (in shares)							79,000,000
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Number of shares redeemed (in shares)	600,000
Fixed rate							0.00%
Liquidation preference per share (USD per share)							$ 1,000
Depositary Shares [Member]
Class of Stock [Line Items]
Liquidation preference per share (USD per share)	$ 25	$ 25	$ 1,000	$ 1,000		$ 1,000
Preferred stock, aggregate liquidation preference	$ 600
Number of shares sold (in shares)				2,500,000		2,500,000
Ownership interest	0.25%	0.25%	1.00%	1.00%		1.00%
Series J Preferred Stock [Member]
Class of Stock [Line Items]
Fixed rate							4.45%
Liquidation preference per share (USD per share)		$ 1,000					$ 1,000
Preferred stock, par value (USD per share)		$ 0.01
Proceeds from offering		$ 584
Series I Preferred Stock [Member]
Class of Stock [Line Items]
Fixed rate							4.00%
Liquidation preference per share (USD per share)			$ 100,000				$ 100,000
Preferred stock, par value (USD per share)			$ 0.01
Proceeds from offering			$ 2,200
Series H Preferred Stock [Member]
Class of Stock [Line Items]
Fixed rate				4.00%			4.00%
Liquidation preference per share (USD per share)				$ 100,000			$ 100,000
Preferred stock, par value (USD per share)				$ 0.01
Proceeds from offering				$ 2,470
Series G Preferred Stock [Member]
Class of Stock [Line Items]
Fixed rate						5.375%	5.375%
Liquidation preference per share (USD per share)						$ 100,000	$ 100,000
Preferred stock, par value (USD per share)						$ 0.01
Proceeds from offering						$ 2,470