XML 118 R92.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Income Taxes Changes in Unrecognized Tax Benefits (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Changes in Unrecognized Tax Benefits [Abstract]      
Balance at beginning of year $ 624 $ 609 $ 615
Additions attributable to tax positions taken in the current year 0 8 0
Additions attributable to tax positions taken in prior years 11 7 28
Reduction attributable to tax positions taken in prior years (541) 0 (25)
Lapse of statute 0 0 9
Balance at end of year $ 94 $ 624 $ 609