Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Trade accounts receivable allowance	$ 124	$ 132
Preferred stock, no par value	$ 0	$ 0
Preferred stock, shares authorized	15,000	15,000
Common stock par value	$ 0.01	$ 0.01
Common stock shares authorized	2,000,000	2,000,000
Common stock shares issued	855,700	851,300
Common stock shares outstanding	715,000	711,000
Series A Preferred Stock
Preferred stock, shares outstanding	1,650	1,650
Preferred stock, shares issued	1,650	1,650
Preferred stock, dividend rate, percentage	4.75%	4.75%
Series B Preferred Stock
Preferred stock, shares outstanding	1,720	1,720
Preferred stock, shares issued	1,720	1,720
Preferred stock, dividend rate, percentage	5.00%	5.00%