Retirement and Employee Benefit Plans (Plan Assets Allocation to any Asset Class Falls Outside of the Specified Range) (Details)	12 Months Ended
	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Total target asset allocations	100.00%
Target fixed income and cash and cash equivalents	40.00%
Actual fixed income and cash and cash equivalents	40.00%
Total actual asset allocations	100.00%
Large Cap Growth Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total actual asset allocations	6.00%
Target equity securities	6.00%
Large Cap Value Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total actual asset allocations	6.00%
Target equity securities	6.00%
Large Cap Core Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total actual asset allocations	14.00%
Target equity securities	15.00%
Small Cap Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total actual asset allocations	3.00%
Target equity securities	3.00%
International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total actual asset allocations	26.00%
Target equity securities	25.00%
Emerging Market Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total actual asset allocations	5.00%
Target equity securities	5.00%