Fair Value Measurements and Derivative Instruments (Balance Sheet) (Details) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Derivative Financial Instruments
Asset Derivatives
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Other assets, net of allowances of $42.7 and $71.6 at December 31, 2023 and December 31, 2022, respectively
Liability Derivatives
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Other long-term liabilities
Other Assets
Asset Derivatives
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Derivative financial instruments
Other long-term Liabilities
Liability Derivatives
Derivative Liability, Statement of Financial Position [Extensible Enumeration]		Derivative financial instruments
Designated as Hedging Instrument
Asset Derivatives
Asset Derivatives	[1]	$ 144	$ 204
Liability Derivatives
Liability Derivatives	[1]	66	136
Interest rate swaps | Designated as Hedging Instrument | Derivative Financial Instruments
Asset Derivatives
Asset Derivatives	[1]	1	0
Liability Derivatives
Liability Derivatives	[1]	0	0
Interest rate swaps | Designated as Hedging Instrument | Other Assets
Asset Derivatives
Asset Derivatives	[1]	75	115
Interest rate swaps | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	[1]	0	0
Foreign currency forward contracts | Designated as Hedging Instrument | Derivative Financial Instruments
Asset Derivatives
Asset Derivatives	[1]	20	19
Liability Derivatives
Liability Derivatives	[1]	9	85
Foreign currency forward contracts | Designated as Hedging Instrument | Other Assets
Asset Derivatives
Asset Derivatives	[1]	44	26
Foreign currency forward contracts | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	[1]	4	0
Fuel swaps | Designated as Hedging Instrument | Derivative Financial Instruments
Asset Derivatives
Asset Derivatives	[1]	4	40
Liability Derivatives
Liability Derivatives	[1]	26	46
Fuel swaps | Designated as Hedging Instrument | Other Assets
Asset Derivatives
Asset Derivatives	[1]	0	4
Fuel swaps | Designated as Hedging Instrument | Other long-term Liabilities
Liability Derivatives
Liability Derivatives	[1]	$ 27	$ 5

[1] Subtopic 815-20 “Hedging-General” under ASC 815.