New Accounting Pronouncements Stranded Taxes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
strandedtaxesinAOCI [Line Items]
Other Comprehensive (Income) Loss, Reclassification of Stranded Taxes to Retained Earnings	$ 5,230	$ 0
Subsidiaries [Member]
strandedtaxesinAOCI [Line Items]
Other Comprehensive (Income) Loss, Reclassification of Stranded Taxes to Retained Earnings	27,333	$ 0
Other Comprehensive Income (Loss) Reclassification of Stranded Taxes to RE for Pension Plans	26,200
Other Comprehensive Income (Loss) Reclassification of Stranded Taxes to RE for Interest Rate Swaps	$ 1,100