Employee Benefit Plans (Investments of the Plan Measured at Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 2,306.3	$ 1,988.8	$ 1,910.5
Commingled trusts
Defined Benefit Plan Disclosure [Line Items]
Plan assets	1,060.2	798.6
Commingled trusts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Commingled trusts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	1,060.2	798.6
Commingled trusts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
U.S. government securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets	426.2	414.7
U.S. government securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
U.S. government securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	426.2	414.7
U.S. government securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	355.9	282.1
Mutual funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	10.2	7.3
Mutual funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	345.7	274.8
Mutual funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Corporate and municipal bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	417.2	434.8
Corporate and municipal bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Corporate and municipal bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	417.2	434.8
Corporate and municipal bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Mortgage-backed security bonds
Defined Benefit Plan Disclosure [Line Items]
Plan assets	38.6	38.5
Mortgage-backed security bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Mortgage-backed security bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	38.6	38.5
Mortgage-backed security bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets	0.0	0.0
Total pension asset investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets	2,298.1	1,968.7
Total pension asset investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Plan assets	10.2	7.3
Total pension asset investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Plan assets	2,287.9	1,961.4
Total pension asset investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Plan assets	$ 0.0	$ 0.0