Capitalized Exploratory Well Costs (Tables)

3 Months Ended

Mar. 31, 2019

Extractive Industries [Abstract]

Summary of changes in capitalized well costs

A summary of the changes in our capitalized well costs for the Current Quarter is detailed below. Additions pending the determination of proved reserves excludes amounts capitalized and subsequently charged to expense within the same year.

	2019
	($ in millions)
Balance as of January 1	$	36
Additions pending the determination of proved reserves	7
Divestitures and other	—
Reclassifications to proved properties	(16		)
Charges to exploration expense	—
Balance as of March 31	$	27