Stockholders’ Equity - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions		1 Months Ended		3 Months Ended		9 Months Ended
	Feb. 13, 2020	Oct. 28, 2020	Jul. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 31, 2020	Jan. 31, 2019
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount								$ 5,000,000,000
Value of shares repurchased						$ 1,698,000,000
Shares repurchased (in shares)						42
Accelerated share repurchase, average price per share (in usd per share)			$ 40.77
Number of shares repurchased under the ASR agreement			74
Payments for dividends				$ 111,000,000	$ 115,000,000	$ 337,000,000	$ 360,000,000
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Dividends declared (in usd per share)		$ 0.16
Treasury stock at cost
Equity, Class of Treasury Stock [Line Items]
Value of shares repurchased				1,150,000,000	1,000,000,000	4,700,000,000	4,002,000,000
Additional paid-in capital
Equity, Class of Treasury Stock [Line Items]
Value of shares repurchased				(450,000,000)	$ 0	0	$ 0
Stock Repurchase Program January 2019
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount									$ 4,000,000,000.0
Stock Repurchase Program January 2020
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount								$ 5,000,000,000.0
Accelerated Share Repurchased Agreement
Equity, Class of Treasury Stock [Line Items]
Value of shares repurchased	$ 3,000,000,000.0
Shares repurchased (in shares)	69
Accelerated Share Repurchased Agreement | Treasury stock at cost
Equity, Class of Treasury Stock [Line Items]
Value of shares repurchased	$ 2,550,000,000			$ 450,000,000		$ 3,000,000,000
Shares repurchased (in shares)						74