Common Stock - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020	Dec. 18, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Common stock, shares authorized (in shares)		9,000,000,000.0		9,000,000,000
Common stock, par value (in dollars per share)		$ 1		$ 1
Stock repurchase program, authorized amount			$ 30,000,000,000
Warrant
Class of Stock [Line Items]
Warrants outstanding (in shares)		0		0
Total warrants repurchased (in shares)	0
Common stock
Class of Stock [Line Items]
Common stock capital shares reserved for future issuance (shares)		62,100,000