Equity (Common Stock - Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 11, 2020	Jul. 31, 2019	Nov. 01, 2018	May 22, 2018
Business Acquisition [Line Items]
Common Stock, Shares, Issued	1,181,614,288	1,177,680,299
Cost of shares issued	$ 160	$ 206	$ 89
Stock Repurchase Program, Authorized Amount				$ 3,000	$ 2,000	$ 2,000	$ 1,500
Class of Stock Disclosures [Abstract]
Repurchase amount outstanding	$ 2,800
Repurchase Shares	26,361,487	49,131,501	88,029,138
Treasury Stock, Value, Acquired, Cost Method	$ 1,151	$ 2,285	$ 3,992
Common Shares Issued For Stock Options [Member]
Business Acquisition [Line Items]
Common stock, shares issued	3,933,989	5,856,057	3,114,141
Cost of shares issued	$ 153	$ 199	$ 108
Treasury Shares Issued For Stock Options [Member]
Business Acquisition [Line Items]
Issued Treasury Stock	0	0	0