Employee Benefit Plans - Equity Incentive Plans (Details)	1 Months Ended			12 Months Ended
	May 31, 2020 shares	May 31, 2019 shares	May 31, 2017 shares	Dec. 31, 2020 USD ($) offeringPeriod shares	Dec. 31, 2019 shares	May 31, 2015 shares
Share-Based Compensation Plans
ESPP, offering period (in months)				24 months
ESPP, number of offering period | offeringPeriod				4
ESPP, purchase period (in months)				6 months
ESPP, purchase price (in percentage)				85.00%
Common stock - shares issued (in shares)				327,700,000	335,900,000
Common shares outstanding from equity awards through acquisition (in shares)				5,900,000
Various Acquisitions
Share-Based Compensation Plans
Common shares outstanding from equity awards through acquisition (in shares)				7,300,000
Equity Incentive Plan 2015
Share-Based Compensation Plans
Number of shares authorized (in shares)						38,000,000.0
Additional shares authorized (in shares)		3,700,000	23,000,000.0	0
Aggregate shares subject to outstanding equity awards (in shares)				15,400,000
Number of shares available for future issuance (in shares)				12,100,000	16,600,000
Equity Incentive Plan 1996 and 2006
Share-Based Compensation Plans
Maximum additional shares expired, unexercised, canceled (in shares)						29,000,000.0
Employee Stock Purchase Plan 2008
Share-Based Compensation Plans
Number of shares authorized (in shares)				43,000,000.0
Additional shares authorized (in shares)	8,000,000.0
Number of shares available for future issuance (in shares)				11,500,000
Discount on share purchase price for purchases made under ESPP				15.00%
Periodic payroll deduction - percentage of base salary				10.00%
ESPP individual purchase limits (in shares)				6,000
Period for share purchases under ESPP				12 months
ESPP individual purchase limits | $				$ 25,000
Period for ESPP purchases				1 year
Common stock - shares issued (in shares)				31,500,000