Huawei on Dec 31, 2018 had cash and cash equivalents of CNY184.1 billion. It also had other short term investments of CNY81.8 billion. That is about US$38 billion. Ren has been preparing for war for a decade.
Huawei has about US$10 billion in debt, much of it not due until 2022 or later.
For much more about Huawei finances, check the 2018 annual report.