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Stock Plans (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
Stock Plans (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	May 15, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for grant under the plans (in shares)	9,916,334
Shares available for grant under the plan (in shares)	8,431,504
2024 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for grant under the plans (in shares)	1,151,334			8,765,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	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)	2 years
Cash compensation	$ 23	$ 25
Restricted Stock [Member] \| 2024 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	859,000
Performance Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Measurement period	3 years
Conversion of stock, ratio	1
Compensation expense	$ 25	29
Performance Stock [Member] \| 2024 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	625,000
Performance Stock [Member] \| PSUs 2023 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance metric percent	33.30%
Performance Stock [Member] \| PSUs 2024 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance metric percent	33.30%
Performance Stock [Member] \| PSUs 2025 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance metric percent	50.00%
Performance-Based Restricted Stock [Member] \| Chief Financial Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)			501,000
Minimum [Member] \| Performance Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range, percent of target units	0.00%
Maximum [Member] \| Restricted Stock [Member] \| Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 1	$ 1
Maximum [Member] \| Performance Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range, percent of target units	200.00%