Employee Benefit Plans (Details 7)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Pension Benefits
Used to Determine Benefit Obligations at Measurement Date
Discount rate	3.80%	[1]	4.30%	[1]	5.20%	[1]
Rate of compensation increases					3.50%
Used to Determine Net Periodic Benefit Cost for Years ended December 31
Discount rate	4.30%	[2]	5.20%	[2]	5.70%	[2]
Expected long-term return on plan assets	7.25%		7.75%		8.00%
Rate of compensation increases			3.50%		3.50%
Postretirement Benefits
Used to Determine Benefit Obligations at Measurement Date
Discount rate	3.90%	[1]	4.30%	[1]	5.30%	[1]
Rate of compensation increases	0.00%		0.00%		0.00%
Used to Determine Net Periodic Benefit Cost for Years ended December 31
Discount rate	4.30%	[2]	5.30%	[2]	5.80%	[2]
Expected long-term return on plan assets	0.00%		0.00%		0.00%
Rate of compensation increases	0.00%		0.00%		0.00%

[1] In 2012, 2011 and 2010, the calculated discount rate for the unfunded pension plan was different than the defined benefit pension plan. The calculated rate for the supplemental employee retirement plan was 2.10%, 3.20% and 4.20% in 2012, 2011 and 2010, respectively.

[2] In 2012, 2011 and 2010, the calculated discount rate for the unfunded pension plan was different than the defined benefit pension plan. The calculated rate for the supplemental employee retirement plan was 3.20%, 4.20% and 6.00% in 2012, 2011 and 2010, respectively.