Funds Held for Clients and Corporate Investments (Tables)

12 Months Ended

May 31, 2016

Funds Held for Clients and Corporate Investments [Abstract]

Funds Held for Clients and Corporate Investments

	May 31, 2016
			Gross		Gross
	Amortized		unrealized		unrealized		Fair
In millions	cost		gains		losses		value
Type of issue:
Funds held for clients money market securities and other    cash equivalents	$	502.4	$	—	$	—	$	502.4
Available-for-sale securities:
Corporate bonds		128.4		2.9		(0.1)		131.2
General obligation municipal bonds		1,594.1		27.6		(0.1)		1,621.6
Pre-refunded municipal bonds(1)		60.2		1.4		—		61.6
Revenue municipal bonds		916.2		15.8		(0.2)		931.8
U.S. government agency securities		160.8		0.6		(0.3)		161.1
Variable rate demand notes		1,234.6		—		—		1,234.6
Total available-for-sale securities		4,094.3		48.3		(0.7)		4,141.9
Other		14.2		0.8		(0.1)		14.9
Total funds held for clients and corporate investments	$	4,610.9	$	49.1	$	(0.8)	$	4,659.2

	May 31, 2015
			Gross		Gross
	Amortized		unrealized		unrealized		Fair
In millions	cost		gains		losses		value
Type of issue:
Funds held for clients money market securities and other    cash equivalents	$	1,430.0	$	—	$	—	$	1,430.0
Available-for-sale securities:
General obligation municipal bonds		1,694.0		14.0		(4.3)		1,703.7
Pre-refunded municipal bonds(1)		101.7		1.0		—		102.7
Revenue municipal bonds		960.7		6.1		(3.2)		963.6
Variable rate demand notes		825.6		—		—		825.6
Total available-for-sale securities		3,582.0		21.1		(7.5)		3,595.6
Other		12.7		1.5		—		14.2
Total funds held for clients and corporate investments	$	5,024.7	$	22.6	$	(7.5)	$	5,039.8

(1) Pre-refunded municipal bonds are secured by an escrow fund of U.S. government obligations.

Classification of Investments on Consolidated Balance Sheets

	May 31,
In millions	2016		2015
Funds held for clients	$	3,997.5	$	4,273.4
Corporate investments		220.6		366.6
Long-term corporate investments		441.1		399.8
Total funds held for clients and corporate investments	$	4,659.2	$	5,039.8

Securities in Unrealized Loss Position

	May 31, 2016
	Securities in an unrealized  loss position for less than  twelve months				Securities in an unrealized  loss position for more than  twelve months				Total
	Gross				Gross				Gross
	unrealized		Fair		unrealized		Fair		unrealized		Fair
In millions	losses		value		losses		value		losses		value
Type of issue:
Corporate bonds		(0.1)		14.7		—		—		(0.1)		14.7
General obligation municipal bonds	$	(0.1)	$	48.9	$	—	$	2.8	$	(0.1)	$	51.7
Pre-refunded municipal bonds		—		5.7		—		—		—		5.7
Revenue municipal bonds		—		20.7		(0.2)		11.7		(0.2)		32.4
U.S. government agency securities		(0.3)		51.1		—		—		(0.3)		51.1
Total	$	(0.5)	$	141.1	$	(0.2)	$	14.5	$	(0.7)	$	155.6

	May 31, 2015
	Securities in an unrealized  loss position for less than  twelve months				Securities in an unrealized  loss position for more than  twelve months				Total
	Gross				Gross				Gross
	unrealized		Fair		unrealized		Fair		unrealized		Fair
In millions	losses		value		losses		value		losses		value
Type of issue:
General obligation municipal bonds	$	(3.8)	$	535.1	$	(0.5)	$	26.3	$	(4.3)	$	561.4
Revenue municipal bonds		(3.2)		361.6		—		—		(3.2)		361.6
Total	$	(7.0)	$	896.7	$	(0.5)	$	26.3	$	(7.5)	$	923.0

Realized Gains and Losses from Sale of Available-for-sale Securities

	Year ended May 31,
In millions	2016		2015		2014
Gross realized gains	$	0.1	$	0.3	$	0.6
Gross realized losses		—		—		—
Net realized gains	$	0.1	$	0.3	$	0.6

Amortized Cost and Fair Value of Available-for-sale Securities by Contractual Maturity

	May 31, 2016
	Amortized		Fair
In millions	cost		value
Maturity date:
Due in one year or less	$	359.6	$	360.7
Due after one year through three years		742.7		749.4
Due after three years through five years		918.5		935.7
Due after five years		2,073.5		2,096.1
Total	$	4,094.3	$	4,141.9