Business Combinations Business Combinations (Consideration Transferred) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Business Combination, Purchase Price Consideration [Line Items]
Payments to Acquire Businesses, Gross	$ 832.5
Cash Acquired from Acquisition	(28.0)	[1]
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination	804.5
Common Class A [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	482.9	[2]
Stock Option Awards [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	16.1	[3]
Senior Notes [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	243.0	[4]
Convertible Debt [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	19.3	[5]
Revolving Credit Facility [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	63.4	[6]
Acquisition-related Costs [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	$ 7.8	[7]

[1] Represents the Stream cash balance acquired at acquisition.

[2] The cash consideration for the outstanding shares of Stream's common stock, which includes a preliminary estimate for future working capital settlement. Stream outstanding common shares totaled 0.7 as of March 3, 2014.

[3] The cash consideration paid per share of "in the money" stock option awards.

[4] The cash consideration to repay Stream's 11.25% Senior Secured Notes due 2014, which reflects the aggregate principal and interest amounts of $230.0 and $13.0, respectively, as of March 3, 2014.

[5] The cash consideration to repay Stream's 10.0% Promissory Notes, which reflects the aggregate principal and interest amounts of $16.1 and $3.2, respectively, as of March 3, 2014.

[6] The cash consideration to repay Stream's Revolving Credit Facility, which reflects the aggregate principal and interest amounts of $63.1 and $0.3, respectively, as of March 3, 2014.

[7] Pursuant to the Merger Agreement, Convergys reimbursed the holders of Stream common stock for expenses incurred by Stream in connection with the merger. These expenses primarily related to third-party consulting services.