The commonly cited SIPRI military expenditure database counts military retirement benefits (as well as spending for PAP, coast guard, etc.) in their estimate of Chinese military spending but do not include them for the US (or most other countries). The $1.5 trillion number for total US military spending is from applying the same methodology that SIPRI applies to Chinese military spending.
Also, the high amount of US Veteran Affairs spending is the direct result of all the wars that the US fought since 9/11, with the majority of the expenses going to taking care of veterans with long term disability and health issues suffered in those wars. As a result of these wars, the US VA budget ballooned from $45 billion in FY 2001 to a requested
.
The US Coast Guard have fought in every major US war since WW2, including in Afghanistan, a landlocked country.