Significant business acquisitions - Narrative (Detail) $ in Millions				1 Months Ended		11 Months Ended	12 Months Ended
	Sep. 01, 2023 USD ($)	Jan. 31, 2023 USD ($)	Oct. 19, 2022 USD ($)	Jan. 31, 2024 USD ($)	Jan. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) Store Location	Dec. 31, 2023 USD ($) Store Location	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Aug. 31, 2023
Business Acquisition [Line Items]
Revenues							$ 254,906	$ 207,771	$ 191,252
Net Income (Loss)							$ 96,223	$ (22,759)	$ 89,937
Alleghany Corporation [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition			Oct. 19, 2022
Business acquisition, cash consideration			$ 11,500
Pilot Travel Centers LLC [Member]
Business Acquisition [Line Items]
Percentage of additional interest acquired		41.40%
Business acquisition, cash consideration		$ 8,200
Economic interest		38.60%			38.60%	38.60%	38.60%
Economic interest after subsequent acquisition		80.00%			80.00%
Revenues						$ 51,700
Net Income (Loss)						$ 603
One-time, non-cash remeasurement gain recognized					$ 3,000
Pilot Travel Centers LLC [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Business acquisition, cash consideration				$ 2,600
Economic interest after subsequent acquisition				100.00%
Pilot Travel Centers LLC [Member] | U.S. and Canada [Member]
Business Acquisition [Line Items]
Number of fuel only retail locations | Location						75	75
Pilot Travel Centers LLC [Member] | Travel Center Locations [Member] | U.S. States [Member]
Business Acquisition [Line Items]
Number of places retail locations located | Location						44	44
Pilot Travel Centers LLC [Member] | Travel Center Locations [Member] | Canadian Provinces [Member]
Business Acquisition [Line Items]
Number of places retail locations located | Location						5	5
Pilot Travel Centers LLC [Member] | Minimum [Member] | Travel Center Locations [Member] | U.S. and Canada [Member]
Business Acquisition [Line Items]
Number of retail | Store						650	650
Berkshire Hathaway Energy [Member] | Cove Point LNG LP [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition	Sep. 01, 2023
Business acquisition, cash consideration	$ 3,300
Excess consideration paid for acquiring noncontrolling Interest	$ 667
Berkshire Hathaway Energy [Member] | Cove Point LNG LP [Member] | General Partner [Member] | Cove Point [Member]
Business Acquisition [Line Items]
Economic interest	100.00%
Berkshire Hathaway Energy [Member] | Cove Point LNG LP [Member] | Limited Partner [Member]
Business Acquisition [Line Items]
Percentage of additional interest acquired	50.00%
Economic interest										25.00%
Economic interest after subsequent acquisition	75.00%