Commitments and Contingent Liabilities Rights-of-way obligations (Details) $ in Millions	Dec. 31, 2019 USD ($)
Class of Warrant or Right [Line Items]
Lessee, Operating Lease, Liability, Payments, Due	$ 467
ROW
Class of Warrant or Right [Line Items]
Lessee, Operating Lease, Liability, Payments, Due	$ 202

Amount of lessee's undiscounted obligation for lease payments for operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918701-209980

Name:	us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant