Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 1,531.6	$ 1,389.8	$ 1,054.9	$ 1,017.4	$ 1,361.9	$ 1,249.9	$ 968.7	$ 948.6	$ 4,993.7	$ 4,529.0	$ 4,362.2
Distribution revenues
Disaggregation of Revenue [Line Items]
Revenues									1,555.3	1,451.2	1,459.8
Foreign currency exchange
Disaggregation of Revenue [Line Items]
Revenues									131.9	136.4	102.4
Recurring fee revenues
Disaggregation of Revenue [Line Items]
Revenues									3,332.9	3,036.3	2,760.3
Event-driven fee revenues
Disaggregation of Revenue [Line Items]
Revenues									237.3	178.0	244.5
Investor Communication Solutions
Disaggregation of Revenue [Line Items]
Revenues									3,867.5	3,491.3	3,468.3
Investor Communication Solutions | Total ICS Recurring fee revenues
Disaggregation of Revenue [Line Items]
Revenues									2,074.8	1,862.0	1,764.0
Investor Communication Solutions | Regulatory
Disaggregation of Revenue [Line Items]
Revenues									953.6	792.5	750.4
Investor Communication Solutions | Data-driven fund solutions
Disaggregation of Revenue [Line Items]
Revenues									358.0	339.4	303.9
Investor Communication Solutions | Issuer
Disaggregation of Revenue [Line Items]
Revenues									189.0	156.7	137.1
Investor Communication Solutions | Customer communications
Disaggregation of Revenue [Line Items]
Revenues									574.2	573.4	572.6
Investor Communication Solutions | Total ICS Event-driven fee revenues
Disaggregation of Revenue [Line Items]
Revenues									237.3	178.0	244.5
Investor Communication Solutions | Equity and other
Disaggregation of Revenue [Line Items]
Revenues									124.6	79.5	107.3
Investor Communication Solutions | Mutual funds
Disaggregation of Revenue [Line Items]
Revenues									112.8	98.5	137.2
Investor Communication Solutions | Distribution revenues
Disaggregation of Revenue [Line Items]
Revenues									1,555.3	1,451.2	1,459.8
Global Technology and Operations
Disaggregation of Revenue [Line Items]
Revenues									4,993.7	4,529.0	4,362.2
Global Technology and Operations | Total GTO Recurring fee revenues
Disaggregation of Revenue [Line Items]
Revenues									1,258.1	1,174.2	996.3
Global Technology and Operations | Capital markets
Disaggregation of Revenue [Line Items]
Revenues									700.5	650.2	590.6
Global Technology and Operations | Wealth and investment management
Disaggregation of Revenue [Line Items]
Revenues									$ 557.6	$ 524.0	$ 405.7