Contractual Commitments, Contingencies And Off-Balance Sheet Arrangements (Narrative) (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Contractual Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Expenses recorded related to agreement			$ 27.6	$ 27.3	$ 56.4	$ 54.5
Expected contract extension costs maximum	10
Cost of IBM data center capitalized		28.5
IT Services Agreement [Member]
Contractual Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Expiration date on agreement					June 30, 2022
Commitments under agreement					539.3
Expenses recorded related to IT services			$ 3.7		$ 6.9
Automatic Data Processing [Member]
Contractual Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Expiration date on agreement					June 30, 2012