Benefit Plans (Narratives) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2012
Compensation and Retirement Disclosure [Abstract]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 10.0
Matching Contribution to the Savings Plan	contribution to $.50 for each $1.00 up to 1% of an employee’s qualifying salary

The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan in the current remaining fiscal period. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.

No definition available.

Name:	us-gaap_DefinedBenefitPlanEstimatedFutureEmployerContributionsInCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant