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Stock Plans (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
Stock Plans (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
2021 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under the plan (in shares)	4,155,000
Shares authorized for grant under the plans (in shares)	15,600,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years	3 years	3 years
Remaining unrecognized compensation cost associated with unvested restricted stock awards	$ 46
Weighted average period over which unvested restricted stock awards unrecognized compensation cost is expected to be recognized (in years)	1 year
Cash compensation	$ 29	$ 27
Restricted Stock [Member] \| Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 1
Performance Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period	3 years
Performance metric percent	33.30%
Conversion of stock, ratio	1
Compensation expense	$ 52	$ 27
Minimum [Member] \| Performance Stock [Member] \| PSUs 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range, percent of target units	0.00%
Minimum [Member] \| Performance Stock [Member] \| PSUs 2022 And 2023 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range, percent of target units	0.00%
Maximum [Member] \| Performance Stock [Member] \| PSUs 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range, percent of target units	300.00%
Maximum [Member] \| Performance Stock [Member] \| PSUs 2022 And 2023 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range, percent of target units	200.00%