Retirement and Employee Benefit Plans (Changes in Plans Benefit Obligations, Fair Value of Assets, and Funded Status) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in plan assets:
Other employee-related liabilities	$ 1.0	$ 1.0
Pension Benefits
Change in benefit obligations:
Benefit obligation at January 1	139.0	126.0
Service cost	0.0	7.0	$ 7.0
Interest cost	4.0	5.0	5.0
Participant contributions	0.0	0.0
Actuarial (gain) loss	(4.0)	16.0
Benefits paid	(2.0)	(13.0)
Plan amendments	0.0	0.0
Curtailments	0.0	(2.0)
Settlements	(11.0)	0.0
Benefit obligation at December 31	126.0	139.0	126.0
Change in plan assets:
Fair value of plan assets at January 1	106.0	96.0
Actual return on plan assets	6.0	11.0
Employer contributions	12.0	12.0
Participant contributions	0.0	0.0
Benefits paid	(2.0)	(13.0)
Settlements	(8.0)	0.0	(21.0)
Fair value of plan assets at December 31	114.0	106.0	96.0
Funded status of plans at December 31 (1)	(12.0)	(33.0)
Other Postretirement Benefits
Change in benefit obligations:
Benefit obligation at January 1	13.0	13.0
Service cost	2.0	2.0	1.0
Interest cost	0.0	0.0	0.0
Participant contributions	0.0	0.0
Actuarial (gain) loss	(2.0)	1.0
Benefits paid	0.0	(1.0)
Plan amendments	0.0	(2.0)
Curtailments	0.0	0.0
Settlements	0.0	0.0
Benefit obligation at December 31	13.0	13.0	13.0
Change in plan assets:
Fair value of plan assets at January 1	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contributions	1.0	1.0
Participant contributions	0.0	0.0
Benefits paid	(1.0)	(1.0)
Settlements	0.0	0.0
Fair value of plan assets at December 31	0.0	0.0	$ 0.0
Funded status of plans at December 31 (1)	$ (13.0)	$ (13.0)