Customer Revenue by Classes of Similar Products or Services (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenue from External Customer [Line Items]
Customer revenue	$ 761.7	$ 809.9
Services
Revenue from External Customer [Line Items]
Customer revenue	690.9	723.0
Technology
Revenue from External Customer [Line Items]
Customer revenue	70.8	86.9
Systems Integration and Consulting | Services
Revenue from External Customer [Line Items]
Customer revenue	211.1	211.7
Outsourcing | Services
Revenue from External Customer [Line Items]
Customer revenue	341.5	361.3
Infrastructure Services | Services
Revenue from External Customer [Line Items]
Customer revenue	92.8	105.1
Core Maintenance | Services
Revenue from External Customer [Line Items]
Customer revenue	45.5	44.9
Enterprise-Class Software And Servers | Technology
Revenue from External Customer [Line Items]
Customer revenue	62.7	80.0
Other Technology | Technology
Revenue from External Customer [Line Items]
Customer revenue	$ 8.1	$ 6.9