v3.19.3.a.u2
Income And Other Taxes (Unrecognized Tax Benefits) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Income And Other Taxes [Abstract]      
Balance at January 1 $ 9,174 $ 8,783 $ 9,468
Additions based on current year's tax positions 287 375 522
Additions for prior years' tax positions 120 240 523
Reductions for prior years' tax positions (97) (125) (865)
Reductions due to lapse of the statute of limitations (279) (5) (113)
Settlements with tax authorities (538) (68) (782)
Foreign exchange effects/other 177 (26) 30
Balance at December 31 $ 8,844 $ 9,174 $ 8,783