Subsequent Event (Details) - USD ($)	Jul. 28, 2021	Jun. 30, 2021	Jun. 30, 2020
Commercial Paper
Subsequent Event [Line Items]
Debt instrument, maximum borrowing capacity			$ 550,000,000
Line of Credit | Revolving Credit Facility
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 550,000,000
Commercial Paper | Commercial Paper
Subsequent Event [Line Items]
Debt instrument, maximum borrowing capacity			$ 550,000,000
Subsequent Event | Line of Credit | Revolving Credit Facility
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 650,000,000
Line of credit facility, term (in years)	5 years
Subsequent Event | Line of Credit | Revolving Credit Facility | Minimum
Subsequent Event [Line Items]
Debt to capitalization ratio not to exceed	0.65
Subsequent Event | Line of Credit | Revolving Credit Facility | Maximum
Subsequent Event [Line Items]
Debt to capitalization ratio not to exceed	1.00
Subsequent Event | Line of Credit | Revolving Credit Facility | LIBOR | Minimum
Subsequent Event [Line Items]
Margin rate	0.00%
Subsequent Event | Line of Credit | Revolving Credit Facility | LIBOR | Maximum
Subsequent Event [Line Items]
Margin rate	0.50%
Subsequent Event | Line of Credit | Revolving Credit Facility | Index Debt Rating | Minimum
Subsequent Event [Line Items]
Margin rate	0.805%
Subsequent Event | Line of Credit | Revolving Credit Facility | Index Debt Rating | Maximum
Subsequent Event [Line Items]
Margin rate	1.50%
Subsequent Event | Commercial Paper | Commercial Paper
Subsequent Event [Line Items]
Debt instrument, maximum borrowing capacity	$ 650,000,000
Debt instrument, term (in days)	397 days