Long-term Debt (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

		December 31, 2023						December 31, 2022
(Dollars in millions)	Interest Rate	Principal		Unamortized Debt Costs		Total		Principal		Unamortized Debt Costs		Total
Debentures:
Senior unsecured notes, maturing 2029, interest rates fixed	3.625%	$	350	$	(3)	$	347	$	350	$	(4)	$	346
Amended Credit Facility, maturing 2028, interest rates variable	varies	—		—		—		—		—		—
Total		350		(3)		347		350		(4)		346
Less: current portion		—				—		—				—
Long-term portion		$	350	$	(3)	$	347	$	350	$	(4)	$	346

Schedule of Maturities of Long-term Debt [Table Text Block]

The weighted average interest rate for all long-term debt at both December 31, 2023 and 2022 was approximately 3.6%. Required repayment of principal for long-term debt is as follows (dollars in millions):

Years ending December 31,
2024	$	—
2025	—
2026	—
2027	—
2028	—
2029 and thereafter	350
Total	$	350