Common and Preferred Shares - Common Shares (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity [Abstract]
Common shares, authorized (in shares)	3,600	3,600	3,600
Schedule Of Stock By Class [Roll Forward]
Shares issued and outstanding at beginning of year (in shares)	723	743	761
Repurchases of common shares (in shares)	(24)	(22)	(20)
Net shares issued for RSUs and stock option exercises (in shares)	3	2	2
Shares issued and outstanding as of December 31 (in shares)	702	723	743
Shares reserved for issuance under employee stock and employee benefit plans (in shares)	27