Commitments, Guarantees and Contingencies - Legal Proceedings (Details) - U.S. Water Services [Member] - U.S. Water Services Patent Defense Litigation [Member] $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Legal Proceedings [Line Items]
Patents Infringed	2
Addition to Intangible Assets for Patent Defense Costs	$ 2.6

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_GainContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration