Debt (Narrative) (Details) - USD ($)	1 Months Ended
	Oct. 31, 2023	Nov. 30, 2022	Dec. 31, 2023	Nov. 30, 2023	Sep. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Oct. 31, 2022	Sep. 30, 2022
Debt Instrument [Line Items]
Commercial paper outstanding			$ 0				$ 0
Repayments of principal in 2024			1,600,000,000
Repayments of principal in 2025			518,000,000
Repayments of principal in 2026			1,200,000,000
Repayments of principal in 2027			21,000,000
Repayments of principal in 2028			21,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, term	5 years
Revolving credit facility, borrowing capacity	$ 3,500,000,000
New Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, borrowing capacity					$ 2,800,000,000
Uncommitted Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, term	1 year
Amended Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, amount outstanding			0				0
Other Debt Facilities
Debt Instrument [Line Items]
Revolving credit facility, amount outstanding			0				0
Debt instrument, unused borrowing capacity			113,000,000				362,000,000
Letters of credit outstanding, amount			$ 139,000,000				$ 152,000,000
4.05% Senior Debt Obligations October 2023
Debt Instrument [Line Items]
Interest rate	4.05%
4.05% Senior Debt Obligations October 2023 | Senior Notes
Debt Instrument [Line Items]
Repayments of debt	$ 250,000,000
Senior notes – 5.400% due 2033
Debt Instrument [Line Items]
Interest rate			5.40%		5.40%
Senior notes – 5.400% due 2033 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, amount					$ 600,000,000
5.700% Senior Debt Obligations Due 2053
Debt Instrument [Line Items]
Interest rate					5.70%
5.700% Senior Debt Obligations Due 2053 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, amount					$ 1,000,000,000
Senior notes – 5.450% due 2053
Debt Instrument [Line Items]
Interest rate			5.45%			5.45%
Senior notes – 5.450% due 2053 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, amount						$ 600,000,000
Senior notes – 5.750% due 2032
Debt Instrument [Line Items]
Interest rate			5.75%					5.75%
Senior notes – 5.750% due 2032 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, amount								$ 500,000,000
Senior notes – 6.25% due 2052
Debt Instrument [Line Items]
Interest rate			6.25%					6.25%
Senior notes – 6.25% due 2052 | Senior Notes
Debt Instrument [Line Items]
Debt instrument, amount								$ 500,000,000
3.30% Senior Debt Obligations Due March 2023
Debt Instrument [Line Items]
Repayments of debt		$ 350,000,000
Interest rate		3.30%
Commercial Paper
Debt Instrument [Line Items]
Short-term debt	$ 2,800,000,000			$ 3,500,000,000				$ 2,800,000,000	$ 2,000,000,000