Profit per share (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2024		Dec. 31, 2023	Dec. 31, 2022	Aug. 01, 2022	May 31, 2022	Jul. 01, 2018
Stock repurchase
Common shares under SARs and stock options not included in the computation of diluted earnings per share (in shares)				300,000		800,000	2,000,000.0
Common shares repurchased (in shares)				23,417,282		19,466,020	21,882,818
Common shares repurchased				$ 7,997	[1]	$ 4,675	$ 4,230
Payments for repurchase of common stock				7,697		$ 4,975	$ 4,230
2018 Authorization Program
Stock repurchase
Authorized amount										$ 10,000
Remaining authorized repurchase								$ 70
2022 Authorization Program
Stock repurchase
Authorized amount									$ 15,000
Remaining authorized repurchase	$ 20,100			$ 20,100
2024 Authorization Program
Stock repurchase
Authorized amount		$ 20,000
ASR Agreements
Stock repurchase
Common shares repurchased (in shares)	3,600,000	2,200,000	7,600,000
Common shares repurchased		$ 750	$ 2,450
Payments for repurchase of common stock		$ 1,000	$ 3,500

[1] See Note 16 regarding shares repurchased.