Investments Summary of Significant Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Revenues	$ 4,906	$ 4,898	$ 4,406
Costs and expenses	3,508	3,245	3,219
Net income	1,398	1,653	$ 1,187
Current assets	1,195	1,422
Non-current assets	24,743	22,615
Current liabilities	2,125	2,683
Non-current liabilities	9,670	9,484
Partners’/owners’ equity	$ 14,143	$ 11,870