Retirement Benefits - Summary of Basis Used to Measure Defined Benefit Plans Assets at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	$ 63.1	$ 142.1
U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.3	3.7
U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	4.6	0.4
International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	4.2	10.4
U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	1.9	14.3
U.S. Long Term
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	5.4	51.9
U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.7	0.3
International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	7.5	8.4
Other Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	23.7	20.7
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	12.1	28.5
Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	2.7	3.5
Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	12.6	36.2
Level 1 | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.3	3.7
Level 1 | U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 1 | International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	1.0	4.4
Level 1 | U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 1 | U.S. Long Term
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 1 | U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 1 | International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.3	0.3
Level 1 | Other Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	11.0	27.8
Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	26.8	85.2
Level 2 | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 2 | U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	4.6	0.4
Level 2 | International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	3.2	6.0
Level 2 | U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	1.9	14.3
Level 2 | U.S. Long Term
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	5.4	51.9
Level 2 | U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.7	0.3
Level 2 | International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	7.2	8.1
Level 2 | Other Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	1.1	0.7
Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	2.7	3.5
Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	23.7	20.7
Level 3 | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | U.S. Long Term
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | Other Commingled Funds
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	23.7	20.7
Level 3 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0.0	0.0
Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	$ 0.0	$ 0.0