pre_text: Interest Expense NM-not meaningful Interest expense increased $621 million compared to 2018. Interest expense is presented in cost of financing in the Consolidated Income Statement only if the related external borrowings are to support the Global Financing external business. Overall interest expense (excluding capitalized interest) in 2019 was $1,952 million, an increase of $473 million year to year, driven by a higher average debt balance and higher interest rates as we issued debt to finance the Red Hat acquisition. Operating (non-GAAP) interest expense increased $393 million compared to the prior-year period. It excludes the Red Hat pre-closing debt financing costs.
table: ($ in millions)
table: For the year ended December 31: 2019 2018 Yr.-to-Yr. Percent Change
table: Interest expense $1,344 $723 85.9%
table: Non-operating adjustment
table: Acquisition-related charges (228) — NM
table: Operating (non-GAAP) interest expense $1,116 $723 54.4
question: Analyse this data from a financial earnings document. What was the average Interest expense?