Business Description and Summary of Significant Accounting Policies: Property, Plant and Equipment (Details)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Composite Depreciation Rate for Plants in Service	2.30%	2.10%	2.20%

Composite depreciation rate for public utility plants in service.

No definition available.

Name:	us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration