Employee Benefit Plans Employee Benefit Plans (Investments of the Plan Measured at Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 2,138.4	$ 2,006.3	$ 2,009.8
Comingled Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,338.5	1,029.2
Comingled Trusts [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Comingled Trusts [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,338.5	1,029.2
Comingled Trusts [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	337.7	371.5
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	337.7	371.5
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4.8	76.6
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4.8	76.6
Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Corporate And Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	409.3	433.4
Corporate And Municipal Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Corporate And Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	409.3	433.4
Corporate And Municipal Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	32.9	35.3
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	32.9	35.3
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	0.0	0.0
Total Pension Assets Excluding Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,123.2	1,946.0
Total Pension Assets Excluding Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4.8	76.6
Total Pension Assets Excluding Cash [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,118.4	1,869.4
Total Pension Assets Excluding Cash [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 0.0	$ 0.0