CONSOLIDATED BALANCE SHEETS (Parenthetical) $ in Millions	Sep. 30, 2020 USD ($) shares	Sep. 30, 2020 SFr / shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2019 SFr / shares
CONSOLIDATED BALANCE SHEETS
Allowance for doubtful accounts | $	$ 2
Materials and supplies, allowance for obsolescence | $	$ 118		$ 127
Shares, CHF par value (in Swiss francs per share) | SFr / shares		SFr 0.10		SFr 0.10
Shares, authorized	824,648,925		639,674,422
Shares, conditionally authorized	142,365,398		142,365,398
Shares, issued	639,674,414		617,970,525
Shares, outstanding	614,861,972		611,871,374