Business Combination Purchase Price Consideration (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
		Mar. 31, 2014	Dec. 31, 2014
Business Combination, Purchase Price Consideration [Line Items]
Transaction Cost of Equity Method Investment Sold			$ 830.6
Equity Method Investment, Realized Gain (Loss) on Disposal	[1]	$ 28.0
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination			$ 802.6
Common Class A [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	[2]	481.0
Stock Option Awards [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	[3]	16.1
Senior Notes [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	[4]	243.0
Convertible Debt [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	[5]	19.3
Revolving Credit Facility [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	[6]	63.4
Acquisition-related Costs [Member]
Business Combination, Purchase Price Consideration [Line Items]
Business Combination, Consideration Transferred, Liabilities Incurred	[7]	$ 7.8

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

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

[3] The cash consideration paid for “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.