Pension, Postretirement, Other Postemployment, and Employee Savings Plan Benefits (Details 4) (Qualified Pension Plans)	Dec. 31, 2011	Dec. 31, 2010
Disclosures by plan assets
Target Allocation (as a percent)	100.00%	100.00%
Actual Allocation (as a percent)	100.00%	100.00%
Global equity securities
Disclosures by plan assets
Target Allocation (as a percent)	42.00%	42.00%
Actual Allocation (as a percent)	38.00%	42.00%
Fixed income securities
Disclosures by plan assets
Target Allocation (as a percent)	40.00%	40.00%
Actual Allocation (as a percent)	42.00%	37.00%
Alternative investments
Disclosures by plan assets
Target Allocation (as a percent)	12.00%	12.00%
Actual Allocation (as a percent)	11.00%	8.00%
High yield bonds
Disclosures by plan assets
Target Allocation (as a percent)	6.00%	6.00%
Actual Allocation (as a percent)	6.00%	6.00%
Cash and cash equivalents
Disclosures by plan assets
Actual Allocation (as a percent)	3.00%	7.00%