Stock Plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, in years	3 years
Expense amortization period	3 years
Pre-tax compensation expense	$ 47	$ 41	$ 34
Deferred tax benefit	12	10	9
Unamortized compensation expense	$ 77
Weighted-average period of recognition, in years	2 years
Weighted-average grant date fair value	$ 56	$ 59	$ 48
Weighted-average grant date fair value, per share (in USD per share)	$ 46.38	$ 49.22	$ 45.22
Total fair value vested	$ 40	$ 29	$ 19
Granted, number of shares (in shares)	1,208,405
Number of shares remaining (in shares)	3,472,801	3,257,795
Grant date fair value (in USD per share)	$ 46.84	$ 46.90
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, in years	3 years
Pre-tax compensation expense	$ 11	$ 9	$ 6
Unamortized compensation expense	$ 15
Granted, number of shares (in shares)	255,601	215,205	229,494
Number of shares remaining (in shares)	713,467
Grant date fair value (in USD per share)	$ 49.22
Common Stock [Member] | 2020 Performance Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares issuable under the stock compensation plan (in shares)	25,000,000
Shares available to be granted (in shares)	20,432,234
Common Stock [Member] | 2015 Directors Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares issuable under the stock compensation plan (in shares)	1,000,000
Shares available to be granted (in shares)	589,927