Apple's Google Cloud annual bill size tbd (see Apple confirms it now uses Google Cloud for iCloud services | The Verge from Feb 2018), but probably less than $9.5B (see Apple may have been paid $9.5B by Google in 2018 to stay default Safari search option | AppleInsider)
"Apple’s future beyond the iPhone increasingly involves software services, ranging from Apple Music and iCloud to its new TV Plus video offering and its News Plus magazine subscription. Yet a big factor in helping those cloud-based services operate across its nearly 1.5 billion active devices simultaneously is the company’s ongoing contract with Amazon, specifically Amazon’s cloud computing division. According to CNBC, Apple is one of Amazon Web Services’ biggest customers, with monthly payments to the cloud division totaling more than $30 million and increasing.Apple’s cloud business is hugely dependent on Amazon | The Verge
Now, CNBC reports that Apple has not publicly said it relies on AWS for more than iCloud. But even still, an expenditure of more than $360 million a year means Apple is deeply reliant on AWS to operate core parts of its business, even though doing so means working with a soon-to-be-rival in online video and a current competitor in areas like artificial intelligence, streaming music, and smart home products."