Debt (Financing Transactions) (Details) € in Millions			1 Months Ended				6 Months Ended
	Jul. 31, 2019 EUR (€)	Jul. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Jul. 31, 2019 GBP (£)	May 31, 2019 USD ($)	May 31, 2019 GBP (£)	Jun. 30, 2019 USD ($) group	Jun. 30, 2018 USD ($)	May 31, 2019 GBP (£)
Debt Instrument [Line Items]
Number of borrowing groups | group							3
Non-cash borrowings and repayments							$ 0	$ 2,453,100,000
Senior Notes
Debt Instrument [Line Items]
Loss on debt modification and extinguishment					$ 48,000,000.0
Payments for debt redemption premium					43,700,000
Write-off of unamortized discounts and deferred financing costs					4,300,000
Senior Notes | Subsequent Event
Debt Instrument [Line Items]
Extinguishment of debt	€ 106.0	$ 120,400,000
VM Dollar Senior Secured Notes | Senior Notes
Debt Instrument [Line Items]
Extinguishment of debt					354,500,000
VM Dollar Senior Secured Notes | Senior Notes | Subsequent Event
Debt Instrument [Line Items]
Extinguishment of debt			$ 447,900,000
VM Sterling Senior Secured Notes | Senior Notes
Debt Instrument [Line Items]
Extinguishment of debt					491,300,000	£ 387,000,000.0
VM Sterling Senior Secured Notes | Senior Notes | Subsequent Event
Debt Instrument [Line Items]
Extinguishment of debt			136,000,000.0	£ 107,100,000
VM Sterling Senior Notes | Senior Notes
Debt Instrument [Line Items]
Extinguishment of debt | £						£ 300,000,000.0
Senior Notes | VM Dollar Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of debt					825,000,000.0
Senior Notes | VM Dollar Senior Secured Notes | Subsequent Event
Debt Instrument [Line Items]
Principal amount of debt		$ 600,000,000.0	$ 600,000,000.0
Senior Notes | VM Sterling Senior Secured Notes
Debt Instrument [Line Items]
Principal amount of debt					$ 380,900,000				£ 300,000,000.0