Corporate Investments And Funds Held For Clients (Corporate Investments And Funds Held For Clients) (Details) (USD $) In Millions	Sep. 30, 2011	Jun. 30, 2011
Schedule of Available-for-sale Securities [Line Items]
Money market securities and other cash equivalents - amortized cost	$ 3,390.7	$ 9,731.8
Money market securities and other cash equivalents - fair value	3,390.7	9,731.8
Available-for-sale securities - amortized cost	16,507.7	16,356.6
Available-for-sale securities - gross unrealized gains	749.2	605.5
Available-for-sale securities - gross unrealized losses	(7.8)	(34.6)
Available-for-sale securities - fair value	17,249.1	16,927.5
Total corporate investments and funds held for clients - amortized cost	19,898.4	26,088.4
Total corporate investments and funds held for clients - gross unrealized gains	749.2	605.5
Total corporate investments and funds held for clients - gross unrealized losses	(7.8)	(34.6)
Total corporate investments and funds held for clients - fair value	20,639.8	26,659.3
U.S. Treasury And Direct Obligations Of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	6,466.3	6,558.2
Available-for-sale securities - gross unrealized gains	277.4	213.0
Available-for-sale securities - gross unrealized losses	(1.0)	(12.1)
Available-for-sale securities - fair value	6,742.7	6,759.1
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	6,297.3	5,908.6
Available-for-sale securities - gross unrealized gains	276.5	234.9
Available-for-sale securities - gross unrealized losses	(6.4)	(16.9)
Available-for-sale securities - fair value	6,567.4	6,126.6
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	375.1	422.4
Available-for-sale securities - gross unrealized gains	22.8	25.4
Available-for-sale securities - fair value	397.9	447.8
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	421.5	476.6
Available-for-sale securities - gross unrealized gains	12.0	15.9
Available-for-sale securities - fair value	433.5	492.5
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	486.9	493.7
Available-for-sale securities - gross unrealized gains	30.1	23.1
Available-for-sale securities - gross unrealized losses	(0.1)	(0.6)
Available-for-sale securities - fair value	516.9	516.2
Canadian Government Obligations And Canadian Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	972.1	1,082.0
Available-for-sale securities - gross unrealized gains	33.2	20.8
Available-for-sale securities - gross unrealized losses		(1.3)
Available-for-sale securities - fair value	1,005.3	1,101.5
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities - amortized cost	1,488.5	1,415.1
Available-for-sale securities - gross unrealized gains	97.2	72.4
Available-for-sale securities - gross unrealized losses	(0.3)	(3.7)
Available-for-sale securities - fair value	$ 1,585.4	$ 1,483.8

Money market securities and other cash equivalents - amortized cost

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Total corporate investments and funds held for clients - amortized cost

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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