Bradley Agreement (Tables)

12 Months Ended

Dec. 31, 2021

Contractors [Abstract]

Schedule of Deficiency Payments made, Net of Reimbursements

The total deficiency repayments (net of payments made), interest and premium received and recognized under the Bradley Agreement for the years ended December 31, 2021, 2020 and 2019, were as follows:

	Year Ended December 31
(millions)	2021		2020		2019
Deficiency repayments		—	$	0.1	$	3.8
Interest		—		0.1		1.0
Premium		—		—		0.4