Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Accounts receivable, allowances for doubtful accounts, billing adjustments and merchant losses	$ 5.1	$ 4.0
Computer software, accumulated amortization	742.5	680.6
Property and equipment, accumulated depreciation and amortization	$ 483.8	$ 457.3
Common stock, par value	$ 0.10	$ 0.10
Common stock, authorized	600,000	600,000
Common stock, issued	202,765	202,769
Common stock, outstanding	183,818	182,781
Treasury stock, shares	18,947	19,988
Other intangible assets
Intangible assets, accumulated amortization	$ 372.9	$ 257.1
Contract Acquisition Costs
Intangible assets, accumulated amortization	$ 305.8	$ 287.9