	Year ended December 31, 2020			Year ended December 31, 2019			Year ended December 31, 2018
Income		34			55			47
Expense		(54	)		(54	)		(54	)
Total		(20	)		1			(7	)

Interest income is related to cash and cash equivalents, short-term deposits and marketable securities held by the Company.

Interest expense recorded in 2020 included a charge of $36 million on the senior unsecured convertible bonds issued on July 3, 2017 and a charge of $9 million on the senior unsecured convertible bonds issued on August 4, 2020, of which $42 million was a non-cash interest expense resulting from the accretion of the discount on the liability component. Interest expense recorded in 2019 and 2018 included a charge of 39 million and $38 million, respectively, on the senior unsecured convertible bonds issued on July 3, 2017, of which $37 million and $36 million, respectively, was a non-cash interest expense resulting from the accretion of the discount on the liability component. Net interest also included charges related to the banking fees and the sale of trade and other receivables.

No borrowing cost was capitalized in 2020, 2019 and 2018. Interest income on U.S. Treasury Bonds classified as available-for-sale marketable securities amounted to $3 million for the year ended December 31, 2020, $6 million for the year ended December 31, 2019 and $6 million for the year ended December 31, 2018.