Social Security is a vital piece of the retirement puzzle, but not the only piece. If you are looking for safe and reliable dividend payers that can supplement the monthly checks you get from Social Security, you’ll want to take a look at high yielders Duke Energy Corp (NYSE: DUK) and Magellan Midstream Partners, L.P. (NYSE: MMP). Not only do both offer big yields, but they have long histories of annual dividend increases too.