Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 2	$ 1
Common Stock, Par or Stated Value Per Share	$ 1.00	$ 1.00
Common Stock, Shares Authorized	200,000,000	200,000,000
Common Stock, Shares, Issued	123,547,974	129,665,899
Common Stock, Shares, Outstanding	111,945,021	111,945,021
Preferred Stock, Par or Stated Value Per Share	$ 1.00	$ 1.00
Preferred Stock, Shares Authorized	15,000,000	15,000,000
Preferred Stock, Shares Issued	0	0
Treasury Stock, Shares	17,307,944	17,720,878

Amount of allowance for credit loss on accounts receivable, classified as current.

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