Investments (Equity Method Investments, Statement of Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments [Abstract]
Total revenue	$ 11,430	$ 6,264	$ 6,392
Total expenses	(5,800)	(3,222)	(2,300)
Net earnings (losses)	5,630	3,042	4,092
Equity in net earnings (losses) included above	525	233	409
Equity in net earnings (losses) of LP/LLC interests not included above	11	14	123
Total equity in net earnings (losses)	$ 536	$ 247	$ 532