Shares and Stockholders' Equity (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2019
Shares and Stockholders' Equity [Abstract]
Deferred compensation plan mark to market adjustment	$ 18
Shares issuable per warrant		1

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

No definition available.

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant