XML 229 R95.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Investments - Securities Accounted for As Available-for-Sale Included in Investments (Parenthetical) (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Fair Value Disclosures [Abstract]    
Gross unrealized losses included in accumulated other comprehensive loss which were in a continuous unrealized loss position for greater than a year   $ 153
Gross unrealized gain included in accumulated other comprehensive gain/(loss) $ 137  
Available-for-sale securities sold 9,580  
Realized gains on sales of available-for-sale securities $ 181