Debt and Credit Facility (Tables)

9 Months Ended

Sep. 30, 2022

Debt Disclosure [Abstract]

Summary of Senior Notes

The following table summarizes key details of our Senior Notes:

				Outstanding (in millions of dollars)
	Issuance Date	Maturity	Effective Interest Rate	As of September 30, 2022			As of December 31, 2021
4.50% Senior Notes	May 2021	June 2031	4.7%	$	550.0		$	550.0
6.50% Senior Notes1	April/May 2020	May 2025	6.8%		—			—
4.625% Senior Notes	November 2019	March 2028	4.8%		500.0			500.0
Total debt					1,050.0			1,050.0
Unamortized issuance costs					(12.4	)		(13.7	)
Total carrying amount				$	1,037.6		$	1,036.3

1In May 2021, we redeemed in full the remaining balance of our 6.50% Senior Notes at a redemption price of 108.83% of the principal amount plus $1.3 million of accrued and unpaid interest for a total net cash outflow of $382.2 million. Upon redemption of the 6.50% Senior Notes, we recorded a loss on extinguishment of debt of $35.9 million within Other income (expense), net, on our Statements of Consolidated Income (Loss), which included the premium payment of $30.9 million and a write-off of the remaining unamortized premium and debt issuance costs of $5.0 million.

Summary of Fair Value of Outstanding Senior Notes

The following table presents the fair value of our outstanding Senior Notes, which are Level 1 liabilities (in millions of dollars):

	As of September 30, 2022		As of December 31, 2021
4.50% Senior Notes	$	399.1	$	542.6
4.625% Senior Notes	$	410.4	$	506.9

Schedule of Availability and Usage of Revolving Credit Facility

The following table summarizes availability and usage of our Revolving Credit Facility as determined by a borrowing base calculated as of September 30, 2022 (in millions of dollars):

Revolving Credit Facility borrowing commitment	$	575.0
Borrowing base availability	$	572.4
Less: Outstanding borrowings under Revolving Credit Facility		—
Less: Outstanding letters of credit under Revolving Credit Facility		(17.4	)
Remaining borrowing availability	$	555.0

Summary of Interest Relating to Senior Notes and Revolving Credit Facility

Interest expense relating to our Senior Notes and Revolving Credit Facility was as follows (in millions of dollars):

	Quarter Ended September 30,						Nine Months Ended September 30,
	2022			2021			2022			2021
Senior Notes interest expense, including debt issuance cost amortization	$	12.4		$	12.4		$	37.2		$	36.6
Revolving Credit Facility commitment fees and finance cost amortization		0.6			0.3			1.6			1.2
Interest expense capitalized as construction in progress		(0.9	)		(0.2	)		(2.3	)		(0.6	)
Total interest expense	$	12.1		$	12.5		$	36.5		$	37.2