Summary of Significant Accounting Policies - Narrative (Details) shares in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2021 USD ($)	Jun. 30, 2021 USD ($) segment shares	Jun. 30, 2020 USD ($) shares	Jun. 30, 2019 USD ($) shares	Jun. 30, 2016 USD ($)	Jun. 30, 2018 USD ($)
Summary of Significant Accounting Policies [Line Items]
Number of reportable segments | segment		2
Percent of level two investment pricing inputs provided by independent pricing service (over)		99.00%
Debt instrument, face amount		$ 3,000,000,000.0
Notes payable		$ 3,006,900,000	$ 2,008,400,000
Options excluded from the calculation of diluted earnings per share because their exercise prices exceeded the average market price (in shares) | shares		1.1	1.2	0.7
Weighted average remaining useful life		6 years
Unrecognized tax benefits		$ 99,900,000	$ 62,300,000	$ 54,200,000		$ 45,200,000
Threshold of coverage for all losses per occurrence covered by reinsurance arrangement, next fiscal year		1,000,000
Concentration risk, credit risk, financial instruments, off-balance sheet risk		273,000,000
Letters of credit outstanding, amount		0
Payments for reinsurance		240,000,000
Threshold for reinsurance per occurrence (up to)		$ 1,000,000
Subsequent Event
Summary of Significant Accounting Policies [Line Items]
Payments for reinsurance	$ 260,000,000
Internal Use Software
Summary of Significant Accounting Policies [Line Items]
Weighted average remaining useful life		10 years
Minimum
Summary of Significant Accounting Policies [Line Items]
Revenue, service agreements, term		30 days
Revenue, remaining performance obligation, expected timing of satisfaction		5 years
Revenue, incremental costs of obtaining a contract, period of recognition		3 years
Revenue, capitalized costs fulfillment period		3 years
Minimum | Internal Use Software
Summary of Significant Accounting Policies [Line Items]
Weighted average remaining useful life		3 years
Maximum
Summary of Significant Accounting Policies [Line Items]
Revenue, service agreements, term		5 years
Revenue, remaining performance obligation, expected timing of satisfaction		7 years
Revenue, incremental costs of obtaining a contract, period of recognition		8 years
Revenue, capitalized costs fulfillment period		8 years
Maximum | Internal Use Software
Summary of Significant Accounting Policies [Line Items]
Weighted average remaining useful life		5 years
Notes due on 2028
Summary of Significant Accounting Policies [Line Items]
Debt instrument, term		7 years
Notes payable		$ 1,000,000,000.0	0
Notes due on 2030
Summary of Significant Accounting Policies [Line Items]
Debt instrument, term		10 years
Notes payable		$ 1,000,000,000.0	0
Notes due on 2025
Summary of Significant Accounting Policies [Line Items]
Debt instrument, term					10 years
Debt instrument, face amount					$ 1,000,000,000.0
Notes payable		$ 1,000,000,000.0	$ 1,000,000,000.0