Significant business acquisitions and other transactions - Summary of preliminary values of identified assets acquired and liabilities assumed (Detail) - USD ($) $ in Millions		Dec. 31, 2024	Dec. 31, 2023	Jan. 31, 2023	Dec. 31, 2022
Assets acquired
Goodwill	[1]	$ 83,880	$ 84,626		$ 78,119
Pilot Travel Centers LLC [Member]
Assets acquired
Property, plant and equipment				$ 8,015
Goodwill				6,605
Other intangible assets				6,853
Other assets				7,047
Assets acquired				28,520
Liabilities assumed and noncontrolling interests
Notes payable				5,876
Other liabilities				4,918
Liabilities assumed				10,794
Noncontrolling interests, predominantly redeemable				3,361
Liabilities assumed and noncontrolling interests				14,155
Net assets				$ 14,365

[1] Net of accumulated goodwill impairments of $11.5 billion as of December 31, 2024, $11.1 billion as of December 31, 2023 and $11.0 billion as of December 31, 2022.