Settlement Assets and Obligations and Non-Settlement Related Investments (Details 1) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 1,525.0
Fair Value		1,529.8
Gross Unrealized Gains		9.3
Gross Unrealized Losses		(4.5)
Net Unrealized Gains		4.8
Settlement Asset Marketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,425.0	$ 1,458.6
Fair Value		1,429.8	1,472.5
Gross Unrealized Gains		9.3	15.2
Gross Unrealized Losses		(4.5)	(1.3)
Net Unrealized Gains		4.8	13.9
State and municipal debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	[1]	1,126.7	1,024.2
Fair Value	[1]	1,131.5	1,038.1
Gross Unrealized Gains	[1]	9.3	15.1
Gross Unrealized Losses	[1]	(4.5)	(1.2)
Net Unrealized Gains	[1]	4.8	13.9
State and municipal variable rate demand notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		247.9	316.8
Fair Value		247.9	316.8
Gross Unrealized Gains		0.0	0.0
Gross Unrealized Losses		0.0	0.0
Net Unrealized Gains		0.0	0.0
Corporate and other debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		50.4	70.5
Fair Value		50.4	70.5
Gross Unrealized Gains		0.0	0.1
Gross Unrealized Losses		0.0	(0.1)
Net Unrealized Gains		0.0	0.0
Short-term state and municipal bond mutual fund [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost			47.1
Fair Value			47.1
Gross Unrealized Gains			0.0
Gross Unrealized Losses			0.0
Net Unrealized Gains			$ 0.0
Time Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		100.0
Fair Value		100.0
Gross Unrealized Gains		0.0
Gross Unrealized Losses		0.0
Net Unrealized Gains		$ 0.0

[1] The majority of these securities are fixed-rate instruments.