Retirement Benefits - Fair values of pension plan assets by asset class (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 3,896,001	$ 3,307,047
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	76,057	46,052
Equity Securities | U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	416,830	292,138
Equity Securities | Non-U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	236,134	191,647
Fixed income securities | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	176,135	141,549
Fixed income securities | Government issued securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	199,389	203,000
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	233,234	246,075
Mutual funds | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	306,168	149,807
Mutual funds | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	204,628	151,649
Common/Collective trusts
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 1,677,942	1,487,170
Investments valued using a net asset value per share, redemption notice period (in days)	60 days
Common/Collective trusts | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 70,389	65,404
Common/Collective trusts | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	46,003	43,981
Limited Partnerships measured at net asset value
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ 262,092	280,248
Investments valued using a net asset value per share, redemption notice period (in days)	95 days
Miscellaneous
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	$ (9,000)	8,327
Quoted Prices In Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	1,592,120	1,155,720
Quoted Prices In Active Markets (Level 1) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	75,370	45,474
Quoted Prices In Active Markets (Level 1) | Equity Securities | U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	416,830	292,138
Quoted Prices In Active Markets (Level 1) | Equity Securities | Non-U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	236,134	191,647
Quoted Prices In Active Markets (Level 1) | Fixed income securities | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	91,982	73,685
Quoted Prices In Active Markets (Level 1) | Fixed income securities | Government issued securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	144,616	141,935
Quoted Prices In Active Markets (Level 1) | Mutual funds | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	306,168	149,807
Quoted Prices In Active Markets (Level 1) | Mutual funds | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	204,628	151,649
Quoted Prices In Active Markets (Level 1) | Common/Collective trusts | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	70,389	65,404
Quoted Prices In Active Markets (Level 1) | Common/Collective trusts | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	46,003	43,981
Quoted Prices In Active Markets (Level 1) | Miscellaneous
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	130,613	137,834
Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	687	578
Significant Other Observable Inputs (Level 2) | Equity Securities | U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0
Significant Other Observable Inputs (Level 2) | Equity Securities | Non-U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0
Significant Other Observable Inputs (Level 2) | Fixed income securities | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	84,153	67,864
Significant Other Observable Inputs (Level 2) | Fixed income securities | Government issued securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	54,773	61,065
Significant Other Observable Inputs (Level 2) | Mutual funds | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Other Observable Inputs (Level 2) | Mutual funds | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Other Observable Inputs (Level 2) | Common/Collective trusts | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Other Observable Inputs (Level 2) | Common/Collective trusts | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Other Observable Inputs (Level 2) | Miscellaneous
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	(9,000)	8,327
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Equity Securities | U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Equity Securities | Non-U.S. based companies
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Fixed income securities | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Fixed income securities | Government issued securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Mutual funds | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Mutual funds | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Common/Collective trusts | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Common/Collective trusts | Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0	0
Significant Unobservable Inputs (Level 3) | Miscellaneous
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	0
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	3,896,001	3,307,047	$ 3,238,307
Company stock included in U.S. based company equity securities	$ 212,480	$ 143,652