Supplemental Financial Information - Noncash Investing and Financing Activities (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplemental Financial Information [Line Items]
Property and equipment and intangible assets accrued but not yet paid	$ 2,000	$ 1,900	$ 1,900
Dividends payable	$ 1,100	$ 1,100	$ 956
Dividends payable (in dollars per share)	$ 0.25	$ 0.23	$ 0.21