Borrowings (Long-term Debt Including Unamortized Debt Discounts and Premiums) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Finance lease liabilities	$ 76	$ 94
Unamortized premium — net	141	180
Debt issuance costs	(98)	(91)
Total long-term debt	20,844	18,914
Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes	20,512	17,768
Senior Notes [Member] | TD Ameritrade Holding [Member]
Debt Instrument [Line Items]
Senior notes	$ 213	963
Senior Notes [Member] | Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.225%
Senior notes	$ 0	256
Senior Notes [Member] | Senior Notes Due 2022 [Member] | TD Ameritrade Holding [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.95%
Senior notes	$ 0	750
Senior Notes [Member] | Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.65%
Senior notes	$ 800	800
Senior Notes [Member] | Senior Notes Due February 2024 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.55%
Senior notes	$ 500	500
Senior Notes [Member] | Senior Notes Due March 2024 [Member]
Debt Instrument [Line Items]
Fixed interest rate	0.75%
Senior notes	$ 1,500	1,500
Senior Notes [Member] | Senior Notes Due April 2024 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.75%
Senior notes	$ 350	350
Senior Notes [Member] | Senior Notes Due April 2024 [Member] | TD Ameritrade Holding [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.75%
Senior notes	$ 50	50
Senior Notes [Member] | Senior Notes Due March 10, 2025 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.00%
Senior notes	$ 375	375
Senior Notes [Member] | Senior Notes Due March 2025 [Member]
Debt Instrument [Line Items]
Fixed interest rate	4.20%
Senior notes	$ 600	600
Senior Notes [Member] | Senior Notes Due April 2025 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.625%
Senior notes	$ 418	418
Senior Notes [Member] | Senior Notes Due April 2025 [Member] | TD Ameritrade Holding [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.625%
Senior notes	$ 82	82
Senior Notes [Member] | Senior Notes Due May 2025 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.85%
Senior notes	$ 750	750
Senior Notes [Member] | Senior Notes Due February 2026 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.45%
Senior notes	$ 350	350
Senior Notes [Member] | Senior Notes Due March 2026 [Member]
Debt Instrument [Line Items]
Fixed interest rate	0.90%
Senior notes	$ 1,250	1,250
Senior Notes [Member] | Senior Notes Due May 2026 [Member]
Debt Instrument [Line Items]
Fixed interest rate	1.15%
Senior notes	$ 1,000	1,000
Senior Notes [Member] | Senior Notes Due March 2, 2027 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.20%
Senior notes	$ 650	650
Senior Notes [Member] | Senior Notes Due March 3, 2027 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.45%
Senior notes	$ 1,500	0
Senior Notes [Member] | Senior Notes Due April, 2027 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.30%
Senior notes	$ 744	744
Senior Notes [Member] | Senior Notes Due April, 2027 [Member] | TD Ameritrade Holding [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.30%
Senior notes	$ 56	56
Senior Notes [Member] | Senior Notes Due January 2028 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.20%
Senior notes	$ 700	700
Senior Notes [Member] | Senior Notes Due March 2028 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.00%
Senior notes	$ 1,250	1,250
Senior Notes [Member] | Senior Notes Due February 2029 [Member]
Debt Instrument [Line Items]
Fixed interest rate	4.00%
Senior notes	$ 600	600
Senior Notes [Member] | Senior Notes Due May 2029 [Member]
Debt Instrument [Line Items]
Fixed interest rate	3.25%
Senior notes	$ 600	600
Senior Notes [Member] | Senior Notes Due October 2029 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.75%
Senior notes	$ 475	475
Senior Notes [Member] | Senior Notes Due October 2029 [Member] | TD Ameritrade Holding [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.75%
Senior notes	$ 25	25
Senior Notes [Member] | Senior Notes Due 2030 [Member]
Debt Instrument [Line Items]
Fixed interest rate	4.625%
Senior notes	$ 500	500
Senior Notes [Member] | Senior Notes Due March 2031 [Member]
Debt Instrument [Line Items]
Fixed interest rate	1.65%
Senior notes	$ 750	750
Senior Notes [Member] | Senior Notes Due May 2031 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.30%
Senior notes	$ 750	750
Senior Notes [Member] | Senior Notes Due December 2031 [Member]
Debt Instrument [Line Items]
Fixed interest rate	1.95%
Senior notes	$ 850	850
Senior Notes [Member] | Senior Notes Due 2032 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.90%
Senior notes	$ 1,000	0
Senior Notes [Member] | Floating Rate Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Senior notes	$ 1,250	1,250
Senior Notes [Member] | Floating Rate Senior Notes Due 2024 [Member] | SOFR [Member]
Debt Instrument [Line Items]
Basis spread rate	0.50%
Senior Notes [Member] | Floating Rate Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Senior notes	$ 500	500
Senior Notes [Member] | Floating Rate Senior Notes Due 2026 [Member] | SOFR [Member]
Debt Instrument [Line Items]
Basis spread rate	0.52%
Senior Notes [Member] | Floating Rate Senior Notes Due 2027 [Member]
Debt Instrument [Line Items]
Senior notes	$ 500	$ 0
Senior Notes [Member] | Floating Rate Senior Notes Due 2027 [Member] | SOFR [Member]
Debt Instrument [Line Items]
Basis spread rate	1.05%