Employee Benefit Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Other post-employment benefit and pension expense	$ (53,228)	$ (6,898)
Qualified Pension Plans
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Service cost	1,593	3,346
Interest cost	3,821	3,811
Expected return on plan assets	(3,834)	(3,565)
Amortization of actuarial loss	1,349	1,855
Amortization of prior service cost	(761)	(344)
Net periodic benefit cost	2,168	5,103
Less capitalized portion	(132)	(81)
Other post-employment benefit and pension expense	2,036	5,022
Post-retirement Healthcare Plans
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Service cost	41	4,355
Interest cost	1,008	4,665
Expected return on plan assets	0	0
Amortization of actuarial loss	31,704	15,036
Amortization of prior service cost	(88,017)	(35,976)
Net periodic benefit cost	(55,264)	(11,920)
Less capitalized portion	0	0
Other post-employment benefit and pension expense	$ (55,264)	$ (11,920)