Operating Segments, Geographic Analysis and Major Customers (Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Operating segments, geographical analysis and major customers
Long-lived assets	$ 21,093	$ 20,809
U.S.
Operating segments, geographical analysis and major customers
Long-lived assets	6,181	7,451
Trinidad
Operating segments, geographical analysis and major customers
Long-lived assets	3,977	1,766
Korea
Operating segments, geographical analysis and major customers
Long-lived assets	1,459	2,048
Other countries
Operating segments, geographical analysis and major customers
Long-lived assets	9,476	9,544
Switzerland
Operating segments, geographical analysis and major customers
Long-lived assets	$ 2	$ 2