XML 156 R136.htm IDEA: XBRL DOCUMENT v3.10.0.1
Income Taxes - U.S. Tax Reform Legislation (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Income Taxes [Abstract]      
Nominal federal income tax rate 21.00% 35.00% 35.00%
Effect of U.S. tax reform legislation   $ 232 $ 0
Effect of U.S. tax reform legislation, measurement period adjustment $ (3)