Significant business acquisitions - Summary of preliminary values of identified assets acquired and liabilities assumed (Detail) - USD ($) $ in Millions		Mar. 31, 2024	[1]	Dec. 31, 2023	[1]	Jan. 31, 2023	Dec. 31, 2022
Assets acquired
Goodwill		$ 84,549		$ 84,626			$ 78,119
Pilot Travel Centers LLC [Member]
Assets acquired
Property, plant and equipment						$ 8,015
Goodwill	[2]					6,605
Other intangible assets						6,853
Other assets						7,047
Assets acquired						28,520
Net assets						14,365
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

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

[2] Goodwill from this acquisition is expected to be deductible for income tax purposes.