Retirement Benefits (Details 1) (Other Postretirement Benefits [Member])	12 Months Ended
	Dec. 31, 2011
Pre-65 [Member]
Weighted average medical care cost trend rates used in measuring the APBO
Initial Cost Trend Rate	8.00%
Ultimate Cost Trend Rate	5.00%
Year That Ultimate Rate Is Reached	2019
Post-65 medical [Member]
Weighted average medical care cost trend rates used in measuring the APBO
Initial Cost Trend Rate	6.00%
Ultimate Cost Trend Rate	5.00%
Year That Ultimate Rate Is Reached	2019
Post-65 prescription [Member]
Weighted average medical care cost trend rates used in measuring the APBO
Initial Cost Trend Rate	6.00%
Ultimate Cost Trend Rate	5.00%
Year That Ultimate Rate Is Reached	2023