Goodwill, Customer Relationships and Other Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($)					3 Months Ended		12 Months Ended
	Oct. 31, 2023	Oct. 31, 2021	Jul. 31, 2021	Jan. 31, 2021	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Goodwill					$ 1,964,000,000		$ 1,964,000,000	$ 12,657,000,000	$ 15,986,000,000
Indefinite-lived intangible assets					9,000,000		9,000,000	9,000,000
Total other intangible assets, net					5,470,000,000		5,470,000,000	6,166,000,000
Goodwill impairment	$ 1,900,000,000	$ 0	$ 0	$ 0		$ 8,800,000,000	10,693,000,000	3,271,000,000	$ 0
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net					3,811,000,000		3,811,000,000	4,574,000,000
Accumulated amortization					4,248,000,000		4,248,000,000	3,606,000,000
Loss on sale of intangible assets					121,000,000		73,000,000
Capitalized Software
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net					1,564,000,000		1,564,000,000	1,482,000,000
Accumulated amortization					4,045,000,000		4,045,000,000	3,895,000,000
Trade Names, Patents and Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net					86,000,000		86,000,000	101,000,000
Accumulated amortization					$ 72,000,000		$ 72,000,000	$ 188,000,000
Fully Amortized and Retired Capitalized Software
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying value										$ 183,000,000
Fully Amortized and Retired Trade Names
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross carrying value										$ 130,000,000