There’s a certain glum symmetry to corporations announcing mergers, layoffs, consolidations, and other restructurings: they also have to disclose how much they expect those restructuring efforts to cost. So we here at Calcbench fired up our Normalized Metrics database to see what the cost of cutting costs has been lately.

Among the S&P 500, total restructuring charges for 2012 through 2015 totaled $84 billion, with an average of $42 million per year—although that average is heavily skewed both ways, with many companies listing no charges for the entire four years, while a handful in any given year might list $1 billion-plus in charges.

Restructuring charges did change from one year to the next, but generally the numbers fluctuated near the neighborhood of $20 billion in total; one can’t say the charges overall are moving up or down:

• 2012: $22.66 billion
• 2013: $18.47 billion
• 2014: $20.39 billion
• 2015: $22.49 billion

Which company took the largest restructuring charge in the last four years? The prize goes to HP Inc. (formerly known as Hewlett-Packard), which incurred $2.27 billion in charges in 2012. That charge was part of a larger three-year plan announced earlier in 2012 that resulted in 55,800 job cuts and $5.5 billion in total charges by the time the plan wrapped up in 2015. Of that $5.5 billion, $4.9 billion was related to workforce reductions, and another $589 million to infrastructure changes (disposing of real estate, equipment, and so forth).

At least, those were the numbers by the time the 2012 restructuring program ended—but how did that restructuring plan evolve over time?

We dug back deeper, to HP’s Form 10-K from 2012 when it first announced the restructuring. Back then, HP predicted 29,000 job cuts and $3.7 billion in charges to be completed by 2014. One year later, the plan numbers had risen to a projected 34,000 job cuts and $4.1 billion in charges.

The big jump came in HP’s 2014 annual report. That’s when the company raised the job cuts to an estimated 55,000, “as HP continues to optimize the workforce and re-engineer business processes to be more competitive and meet its objectives.” HP also raised its expected restructuring costs to $5.5 billion. Those were the final numbers confirmed in the 2015 annual report.

So ends the story of HP’s 2012 Restructuring Plan—but a sequel is in the works. In this year’s annual report HP has detailed the costs of a new three-year restructuring program that is part of its plan to cleave itself into two separate companies. HP’s new plan calls for a workforce reduction of 33,300 employees by 2018, at a cost of $2.9 billion from now through 2018. We’ll keep reading.