Fair Value Measurements (Narratives) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Fair Value Value Measurements
Payments to acquire other securities	$ 7.1	$ 1.2

The cash outflow to acquire securities classified as trading securities and held for investment purposes. Excludes payments for trading securities purchased and held principally for the purpose of selling them in the near term (thus held for only a short period of time).

No definition available.

Name:	us-gaap_PaymentsToAcquireTradingSecuritiesHeldforinvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration