Employee Benefit Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Other post-employment benefit and pension expense	$ (57,568)	$ 19,832	$ (116,926)	$ 56,317
Qualified Pension Plans
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Service cost	1,653	3,514	6,822	11,664
Interest cost	3,702	3,862	11,146	11,788
Expected return on plan assets	(3,688)	(3,368)	(10,911)	(10,179)
Amortization of actuarial loss	1,570	556	5,311	1,634
Amortization of prior service cost	(863)	0	(2,070)	0
Plan curtailment	(4,207)	0	(4,207)	0
Plan settlement	110	650	717	650
Net periodic benefit cost	(1,723)	5,214	6,808	15,557
Less capitalized portion	(137)	(322)	(469)	(1,112)
Other post-employment benefit and pension expense	(1,860)	4,892	6,339	14,445
Post-retirement Healthcare Plans
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Service cost	62	6,279	4,479	18,968
Interest cost	1,005	7,897	6,683	22,520
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	32,775	1,729	80,649	3,576
Amortization of prior service cost	(89,550)	0	(215,076)	0
Plan curtailment	0	0	0	0
Plan settlement	0	0	0	0
Net periodic benefit cost	(55,708)	15,905	(123,265)	45,064
Less capitalized portion	0	(965)	0	(3,192)
Other post-employment benefit and pension expense	$ (55,708)	$ 14,940	$ (123,265)	$ 41,872