BORROWINGS - Narrative (Details)	3 Months Ended		12 Months Ended
	Dec. 31, 2024 USD ($) series	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) series	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
Principal debt issued	$ 9,036,000,000		$ 9,036,000,000	$ 9,452,000,000
Interest expense, long-term debt			580,000,000	616,000,000	$ 54,000,000
Guarantor obligations, maximum exposure				114,000,000
Guarantee obligation, carrying value	3,000,000		3,000,000	4,000,000
Commercial contracts
Debt Instrument [Line Items]
Guarantor obligations, maximum exposure	784,000,000		784,000,000	751,000,000
Equipment residual value obligation
Debt Instrument [Line Items]
Guarantor obligations, maximum exposure	25,000,000		25,000,000	39,000,000
Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Line of credit outstanding	0		0	0
Senior unsecured notes | Senior notes
Debt Instrument [Line Items]
Debt, principal amount	$ 8,250,000,000		$ 8,250,000,000
Number of debt series | series	6		6
Debt repurchase price, percentage			101.00%
4.800% senior notes due August 14, 2029 | Senior notes
Debt Instrument [Line Items]
Debt, principal amount						$ 1,000,000,000
Stated interest rate	4.80%		4.80%			4.80%
Principal debt issued	$ 1,000,000,000		$ 1,000,000,000	0
5.550% senior notes due November 15, 2024 | Senior notes
Debt Instrument [Line Items]
Stated interest rate	5.55%		5.55%
Debt repayments	$ 1,000,000,000
Principal debt issued	0		$ 0	$ 1,000,000,000
5-Year Revolving Credit Facility | Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Debt, term			5 years	5 years
Maximum borrowing capacity	$ 2,500,000,000		$ 2,500,000,000
364-Day Revolving Credit Facility | Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Debt, term	364 days		364 days	364 days
Maximum borrowing capacity	$ 1,000,000,000		$ 1,000,000,000
Floating rate Term Loan Facility due January 2, 2026 | Line of credit
Debt Instrument [Line Items]
Debt repayments	250,000,000	$ 150,000,000
Principal debt issued	750,000,000		$ 750,000,000	$ 1,150,000,000
Floating rate Term Loan Facility due January 2, 2026 | Line of credit | Unsecured debt
Debt Instrument [Line Items]
Debt, term			3 years
Maximum borrowing capacity	$ 2,000,000,000		$ 2,000,000,000