Equity Incentive Plans - Equity Awards (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity Incentive Plans [Abstract]
Compensation expense	$ 120	$ 124	$ 105
Income tax benefits	18	18	17
Cash received from exercise of options	151	111	154
Tax benefit realized on options exercised and release of stock restrictions	$ 37	$ 53	$ 43