v3.20.2
Fair Value Measurement and Disclosure (Gain and Losses on Equity Securities) (Details) - Equity Securities [Member] - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Schedule of Available-for-sale Securities [Line Items]        
Total gains (losses) recognized on equity securities $ 161 $ 50 $ (42) $ 210
Gains (Losses) recognized on equity securities sold 9 9 (24) 27
Unrealized gains (losses) recognized on equity securities held at end of period $ 152 $ 41 $ (18) $ 183