Employee Benefit Plans: Target Plan Assets Allocation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Target Plan Asset Allocations	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Plan Asset Allocations	26.00%	27.00%
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Plan Asset Allocations	5.00%	5.00%
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Plan Asset Allocations	59.00%	58.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Plan Asset Allocations	1.00%	2.00%
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Plan Asset Allocations	9.00%	8.00%