Equity - Rollforward of common stock outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, beginning of year (in shares)	1,906,671,492
Treasury stock, beginning of year (in shares)	(1,172,543,436)
Shares outstanding, beginning of year (in shares)	734,100,000	818,700,000	861,600,000
Shares issued (in shares)	5,500,000	5,500,000	6,800,000
Shares repurchased (in shares)	(50,800,000)	(90,100,000)	(49,700,000)
Shares issued, end of period (in shares)	1,906,671,492	1,906,671,492
Treasury stock, end of period (in shares)	(1,217,831,721)	(1,172,543,436)
Shares outstanding, end of period (in shares)	688,800,000	734,100,000	818,700,000
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, beginning of year (in shares)	1,906,700,000	1,906,700,000	1,906,700,000
Shares issued (in shares)	0
Shares repurchased (in shares)	0
Shares issued, end of period (in shares)	1,906,700,000	1,906,700,000	1,906,700,000
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock, beginning of year (in shares)	(1,172,600,000)	(1,088,000,000)	(1,045,100,000)
Shares issued (in shares)	5,500,000	5,500,000	6,800,000
Shares repurchased (in shares)	(50,800,000)	(90,100,000)	(49,700,000)
Treasury stock, end of period (in shares)	(1,217,900,000)	(1,172,600,000)	(1,088,000,000)