v3.8.0.1
Investments (Equity Method Investments, Statement of Operations) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Investments [Abstract]      
Total revenue $ 6,392 $ 5,360 $ 4,356
Total expenses (2,300) (1,995) (1,803)
Net earnings (losses) 4,092 3,365 2,553
Equity in net earnings (losses) included above 409 247 216
Equity in net earnings (losses) of limited partnership interests not included above 123 103 32
Total equity in net earnings (losses) $ 532 $ 350 $ 248