Equity (Share Repurchases Authorizations) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 05, 2019	Dec. 31, 2016
Under December 2018 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 2,000
Increased Under September 2019 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 2,500
Under December 2017 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount			$ 1,500
Under December 2016 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 1,250
Other common stocks | Increased Under September 2019 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Number of Treasury Stock Shares Acquired	27.2
Other common stocks | Under December 2017 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Number of Treasury Stock Shares Acquired		14.9
Other common stocks | Under December 2016 Board Of Directors Authorization
Equity, Class of Treasury Stock [Line Items]
Number of Treasury Stock Shares Acquired			11.5