Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Communication Breakdown
Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Human Factors; Procedure
Flight ready early. Pushed back 15 mins early with OPS Controller approval. Also notified controller of 2;000 lb extra fuel. Preflight push back and taxi went smoothly. After accepting takeoff clearance we received a ACARS message from OPS asking if we had received DG (Dangerous Goods) paperwork. First Officer and I agreed we thought we did. Uneventful flight and landing.  After level at cruise we inspected DG envelope and found it to be empty. We did have DG manifest signed with employee numbers and DG position summary showing Lithium Ion [Battery] at 12L. ACARS this info to Operations Center and he asked us to complete an ASAP. In summary everything was running super smoothly. Inaccessible DG seems to be every flight and we just assumed ULD DG manifest was in envelope we were given. Will check from now on! The cause of the event Assumed required paperwork was in DG envelope we were handed [was empty.]
Uneventful and smooth preflight; startup; and taxi to Runway XX at ZZZ. After receiving takeoff clearance and approaching the runway threshold we received an ACARS message asking if we had received the DG (Dangerous Goods) paperwork. We both agreed we had and continued to take off. At cruise we discovered that the DG envelope was empty and did not have the Aircraft ULD DG Manifest. We did have the signed Aircraft DG Manifest and the Aircraft DG Position Summary showing lithium battery in position 12L. The ramp agent had placed the DG envelope in the yellow pouch. Poor coordination between flight crew and ramp agent with DG paperwork. [Going forward have] all eyes; flight crew and ramp agent or DG Specialist; must see and account for all DG paperwork.
Flight crew reported a communications breakdown between flight crew and ground personnel resulted in transporting Dangerous Goods [DG] cargo without required DG documents on board.