Stock-Based Compensation Plans (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common share authorized under Convergys LTIP	38.0
Equity compensation plans approved by shareholders
Stock options, common shares to be issued upon exercise	1.2	3.9	5.7	7.8
Total stock, common shares to be issued upon exercise	3.7
Options approved, weighted average exercise price	$ 12.91	$ 23.90	$ 31.66	$ 32.21
Options approved, common shares available, future issuance	10.2
Long-term incentive plan expense related to continuing operations	$ 21.0	$ 17.0	$ 14.8
Long-term incentive plan expense related to discontinued operations	1.4	2.6	3.2
Stock-based compensation expense	21.6	17.4	15.3
Maximum [Member]
Equity compensation plans approved by shareholders
Payout range	200.00%
Minimum [Member]
Equity compensation plans approved by shareholders
Payout range	50.00%
Stock Options [Member]
Equity compensation plans approved by shareholders
Stock options, common shares to be issued upon exercise	1.2
Options approved, weighted average exercise price	$ 12.91
Options approved, common shares available, future issuance	0
Term of Award	10 years
Weighted average grant date, fair value, options outstanding	$ 4.73
Weighted average grant date, fair value, options exercisable	$ 3.99
Aggregate intrinsic value, stock options exercised	3.3	0.7	0.1
Recognized tax benefit from exercised stock	0.7	0.1	0.1
Total grant date fair value of stock options vested			1.1
Aggregate intrinsic value, stock options outstanding and exercisable	4.0
Stock Options [Member] | Maximum [Member]
Equity compensation plans approved by shareholders
Award Vesting Period	3 years
Stock Options [Member] | Minimum [Member]
Equity compensation plans approved by shareholders
Award Vesting Period	2 years
Restricted Stock Units (RSUs) [Member]
Equity compensation plans approved by shareholders
Restricted stock units, common shares to be issed upon exercise	2.5	3.9	4.2
Options approved, weighted average exercise price	$ 0.00
Options approved, common shares available, future issuance	0
Award Maximum Time Until Unvested Performance Shares Are Forfieted	3 years
Expected volatility			56.00%
Expected term (in years)			3 years 0 months
Risk-free interest rate			1.40%
Granted, shares	1.6	1.5	2.3
Restricted stock units granted, weighted average fair value at date of grant	$ 13.11	$ 13.67	$ 11.45
Total unrecognized compensation cost related to non-vested restricted stock and restricted stock units	14.7
Weighted average recognition period (in years)	0.8
Aggregate intrinsic value, non-vested restricted stock	41.7
Restricted Stock [Member] | Maximum [Member]
Equity compensation plans approved by shareholders
Award Vesting Period	5 years
Restricted Stock [Member] | Minimum [Member]
Equity compensation plans approved by shareholders
Award Vesting Period	3 years
Performance Shares [Member]
Equity compensation plans approved by shareholders
Granted, shares	0.6	0.5	1.0
2012 Stock Option Grants [Member] | Stock Options [Member]
Equity compensation plans approved by shareholders
Stock option expense	0.7
Options granted, weighted-average grant date fair value	$ 3.43
Strike price	$ 12.79
Expected volatility	30.74%
Expected term (in years)	4 years 6 months
Risk-free interest rate	0.76%
Expected dividend rate	0.00%
2011 Stock Option Grants [Member] | Stock Options [Member]
Equity compensation plans approved by shareholders
Stock option expense	0.3	1.0
Options granted, weighted-average grant date fair value		$ 4.06
Strike price		$ 13.79
Expected volatility		31.11%
Expected term (in years)		4 years 6 months
Risk-free interest rate		2.12%
Expected dividend rate		0.00%
2010 Stock Options Grants [Member] | Stock Options [Member]
Equity compensation plans approved by shareholders
Stock option expense			$ 1.1