Superman Is Somehow More "Average" Than Captain America
Captain America may just be an average kid in Brooklyn, but his small-town charm lacks one of the secrets Superman has always held.

Warning: SPOILERS for Captain America: Sentinel of Liberty #8
Marvel's Captain America is often thought of as coming from humble beginnings, but Superman somehow beats him in the "normal America" department. Steve Rogers, unlike Iron Man, was not born with any superpowers, but was born on the 4th of July in Brooklyn to Irish immigrant parents (however, this has been heavily hinted at as a fabrication, Captain America's true birthday remains Confidential). Captain America: Sentinel of Liberty #8 shows that Captain America is not as normal as he seems...at least compared to Clark Kent.
In the current comic strip, Captain America is reeling from the shocking betrayal of his former friend Bucky Barnes. The former Winter Soldier is embroiled in an Outer Circle conspiracy: a group of long-lived individuals determined to shape the course of human history after World War I ended. With Bucky Barnes out, Steve must rely on his small group of friends, including Sharon Carter, to stop the machinations of the new Advanced Idea Mechanics (AIM) program. Unfortunately, Captain America wakes up in the near future only to find that his plan has failed before it even started; AIM has established Huge yellow shield over New York.
In Captain America: Sentinel of Liberty #8, created by Jackson Lanzing and Collin Kelly and illustrated by Carmen Carnero, Captain America storms a gas station somewhere in Kansas and asks the attendant to use his phone. When asked for ID, Steve said, "Sir, I don't have a wallet, and I really hate it, but maybe I look a little familiar?" Even though the situation was really bad, Steve accidentally said he Not carrying a wallet or money with him - something his moral counterpart in the DC Universe, Superman, often does.
Captain America Doesn't Carry Money...But Superman Does

In Superman #701 by J. Michael Straczynski, Clark Kent decides to walk across America on foot - not flying, but walking - to reconnect with those he serves. Once, he walked into a restaurant and paid with money hidden in the pocket of his cloak. It's a practical purpose, but also shows that he was raised as Clark Kent rather than Superman, and thus more used to walking around with money (and ID, presumably).
In contrast, Captain America spent most of his life in the U.S. Army or As the leader of the Avengers, he has no secret identity. Whether he likes it or not, Steve Rogers is a celebrity, and frankly, he doesn't need to carry cash or ID, but that doesn't mean he shouldn't. Captain America may have forgotten his childhood roots and necessities, but Superman has not.