Active duty U.S. military personnel traveling on orders to or from duty stations, and active U.S. military dependents traveling on relocation orders, are allowed up to four checked bags in Delta's Economy Class and Delta Connection® carriers (regardless of cabin), and up to five checked bags in First and Business Class on Delta aircraft only, at no charge. Each bag may weigh up to 70 lbs. (32 kg) and measure up to 80 linear inches (203 cm).

Additionally, military personnel traveling on personal business will be allowed two checked bags up to 50 lbs (23 kg) and 62 linear inches (158 cm) at no charge.

YouTube video did not work, but the policy has been this for at least the last month from the last time I looked at it. And I'm sure the travel orders would cover the rest!