Retirement Benefits and Trusteed Assets (Details 11) (Other Postretirement Benefit Plans, Defined Benefit [Member])	12 Months Ended
	Dec. 31, 2011 percent	Dec. 31, 2010 percent	Dec. 31, 2009 percent
Other Postretirement Benefit Plans, Defined Benefit [Member]
Assumptions Used to Determine Projected Benefit Obligation and Benefit Costs [Line Items]
Discount rate	5.00%	5.50%	5.90%
Discount Rate	5.50%	5.90%	6.90%
Expected long-term rate of return on plan assets	8.75%	8.75%	8.80%
Health care trend rate pre and post 65	7.00%	7.00%	7.00%
Ultimate health care trend rate	5.00%	5.00%	5.00%