Stockholders' Equity - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($)
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 589
Initial Board Approval [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Period in Force	3 years
Stock Repurchase Program, Authorized Amount	$ 1,000
Subsequent Board Approved Increase [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Period in Force	3 years
Stock Repurchase Program, Authorized Amount	$ 1,000