CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
CONDENSED CONSOLIDATED BALANCE SHEETS
Allowance for doubtful accounts	$ 26	$ 25
Allowance for other receivables	7	8
Accumulated depreciation and amortization	$ 21,127	$ 20,537
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	630,282,461	630,282,461
Treasury stock, shares	217,005,817	214,158,636