The Merger - Schedule of Purchase Consideration Paid (Details) - Anadarko $ / shares in Units, $ in Millions	Aug. 08, 2019 USD ($) $ / shares shares
Business Acquisition [Line Items]
Total shares of common stock eligible for merger consideration (in shares)	491,600,000
Cash consideration (per share of common stock and shares underlying Anadarko stock-based awards eligible for merger consideration) (usd per share) | $ / shares	$ 59.00
Cash portion of Merger consideration | $	$ 29,002
Total shares of common stock and shares underlying Anadarko stock-based awards eligible for merger consideration (n shares)	492,000,000.0
Exchange ratio (per share of Anadarko common stock)	0.2934
Average share price of Occidental common stock at August 8, 2019 (usd per share) | $ / shares	$ 46.31
Total Merger consideration | $	$ 35,686
Common Stock
Business Acquisition [Line Items]
Total shares of Occidental common stock issued	144,000,000
Average share price of Occidental common stock at August 8, 2019 (usd per share) | $ / shares	$ 46.31
Stock portion of Merger consideration | $	$ 6,684