Debt and Derivatives - Classification and Utilization (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022	May 31, 2022
Debt
Debt maturing or subject to remarketing within twelve months	$ 2,400
Debt classified as long-term due to intent and ability to refinance on long-term basis	2,100
Current portion of long-term debt	297	$ 414
Revolving Credit Facility [Member]
Debt
Maximum capacity	3,500
Outstanding borrowings under credit facility	0
Letters of credit outstanding	181
Unused and available credit capacity	2,800
Term Loan [Member]
Debt
Maximum capacity			$ 1,000
Commercial Paper Program [Member]
Debt
Debt maturing or subject to remarketing within twelve months	$ 489
Debt term	397 days
Commercial paper borrowings	$ 489
Tax Exempt Bonds [Member]
Debt
Debt maturing or subject to remarketing within twelve months	60
Debt with interest rate periods that expire in the next 12 months	1,600
Senior Notes 3.5 % Due 2024 Member
Debt
Debt maturing or subject to remarketing within twelve months	$ 156
Interest rate (as a percent)	3.50%
Other Letter Of Credit Lines [Member]
Debt
Letters of credit outstanding	$ 801
Financing leases and other [Member]
Debt
Debt maturing or subject to remarketing within twelve months	$ 174