Equity, Stock Related Disclosures (Details) - USD ($)		12 Months Ended
	Jan. 26, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 23, 2018	Sep. 21, 2016
Share Activity Rollforward
Treasury stock, beginning balance (shares)		(264,209,742)
Treasury stock, ending balance (shares)		(265,096,171)	(264,209,742)
Equity (Textual)
Preferred stock authorized (shares)		20,000,000
Preferred stock par value per share (in usd per share)		$ 0.01
Preferred stock outstanding (shares)		0	0
Stock repurchases under buyback program		$ 130,000,000	$ 753,000,000	$ 1,511,000,000
Remaining amount authorized under stock purchase program		1,400,000,000
Subsequent Event [Member] | Dividend Declared [Member]
Equity (Textual)
Dividends payable (in usd per share)	$ 0.98
Common Stock Repurchase Programs [Member]
Equity (Textual)
Stock repurchases under buyback program		$ 83,000,000	$ 752,000,000	$ 1,500,000,000
Stock Repurchase Program Approved September 2016 [Member]
Equity (Textual)
Authorized amount under stock purchase programs						$ 2,500,000,000
Stock Repurchase Program Approved January 2018 [Member]
Equity (Textual)
Authorized amount under stock purchase programs					$ 2,500,000,000
Common Stock [Member]
Share Activity Rollforward
Common stock, beginning balance (shares)		673,000,000	673,000,000	673,000,000
Common stock, ending balance (shares)		673,000,000	673,000,000	673,000,000
Treasury Stock [Member]
Share Activity Rollforward
Treasury stock, beginning balance (shares)		(264,000,000)	(256,000,000)	(240,000,000)
Transactions in connection with stock-based compensation plans (shares)		1,000,000	1,000,000
Open market stock purchases (shares)		(2,000,000)	(9,000,000)	(16,000,000)
Treasury stock, ending balance (shares)		(265,000,000)	(264,000,000)	(256,000,000)
Equity (Textual)
Stock repurchases under buyback program		$ 130,000,000	$ 753,000,000	$ 1,511,000,000