Statements Of Consolidated Cash Flows Reconciliation of Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents to the Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2017		Sep. 30, 2016
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 2,363.6		$ 2,776.6
Restricted cash and restricted cash equivalents included in funds held for clients	3,719.6	[1]	3,085.0
Cash, cash equivalents, restricted cash, and restricted cash equivalents, end of period	$ 6,083.2		$ 5,861.6

[1] See Note 6 for a reconciliation of restricted cash and restricted cash equivalents in funds held for clients on the Consolidated Balance Sheets.