Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Name:	us-gaap_StockRepurchasedDuringPeriodShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Net Income (Loss) Per Share - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 13, 2018
Equity, Class of Treasury Stock [Line Items]
Remaining authorized amount	$ 1,100,000,000		$ 1,100,000,000
Common stock repurchase program
Equity, Class of Treasury Stock [Line Items]
Authorized amount					$ 2,000,000,000
Purchases of treasury stock (in shares)	0	0	0	160,000,000
Stock repurchased during period (in shares)	0	0	0	1,511,930