The backgroundTimeRemaining coming very high even if the app is in background

Question

I am trying to print the background remaining time when the application state is background.I am trying to read the time remaining in background to perform certain tasks when the background fetch is triggered.

Here is my code:-

UIApplicationState appState = [[UIApplication sharedApplication] applicationState];

NSString *appStateString;

switch (appState) {
    case UIApplicationStateBackground:
        appStateString = [NSString stringWithFormat: @"background %.02f seconds remaining", [UIApplication sharedApplication].backgroundTimeRemaining];
        break;
}

When i print the value of appStateString I see this:-

background 179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368.00 seconds remaining

As per Apple's documentation it says "While the app is running in the foreground, the value in this property remains suitably large"

But in my case the app is running in background.So why is this value coming so large?Kindly suggest