Energy & Transportation sales (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Energy and transportation sales
Sales and revenues	$ 12,397	$ 9,881	$ 37,173	$ 30,513
Energy & Transportation
Energy and transportation sales
Sales and revenues	4,141	3,475	11,919	10,634
Energy & Transportation | Oil And Gas Customer
Energy and transportation sales
Sales and revenues	1,088	734	3,140	2,622
Energy & Transportation | Power generation
Energy and transportation sales
Sales and revenues	1,010	1,034	3,025	2,783
Energy & Transportation | Industrial
Energy and transportation sales
Sales and revenues	948	730	2,660	2,209
Energy & Transportation | Transportation
Energy and transportation sales
Sales and revenues	$ 1,095	$ 977	$ 3,094	$ 3,020