Fair Value Measurements (Narrative) (Details) shares in Millions	9 Months Ended
Sep. 30, 2021 USD ($) shares
Fair Value Measurements [Abstract]
Cancelled stock incentive plans	$ 0
Number of shares owned \| shares	3.6
Unrealized loss on equity securities	$ 1,600,000

Amount of reorganization items related to pension and other postretirement related charges.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56145-112766

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=124437977&loc=d3e55730-112764

Name:	us-gaap_DebtorReorganizationItemsPensionAndOtherPostretirementRelatedCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration