While it varies from station to station, it is common to receive or ingest the footage by receiving on satellite and recording it for later usage.
Where possible, the TV station will accept the media files from the production house or a distribution service directly. In this case, the media is usually in the MXF or MOV file formats.
The resolution is usually 1280x720 or 1920x1080, with a higher bit-rate ranging between 30 and 100 Mbps.
The only major difference between the consumer deliverable and the format the station has is the bit-rate. The TV station has equipment that can handle the larger files, and has a larger data storage capacity than most normal households. However, a well encoded Blu-ray will contain a close copy of the file the station receives, with an encoded bit-rate between 15 and 45 Mbps.
The main reason for the difference is bandwidth. One 24 minute episode at a bit rate of 145 Mbps stored in uncompressed MXF can be as large as 29 GB. Unfortunately, that has to be compressed in order to get it out to the millions of people that TV stations service.
There isn't an established format that all TV stations receive. It largely depends on the format that can be provided to the station, and what the station is setup to accept regarding equipment.
As Scotty Parker mentioned, a lot of the content is ingested into the studio via satellite. meaning, it's simply recorded as it's airing, like a fancy DVR and a dish that's bigger than average. When this is the case, the recorded format is usually as high as it can be, which is hopefully in most cases HD at 1280x720, or FHD at 1920x1080.
However, an increasingly large number of stations use content that is acquired directly from the production house. Meaning that the company who produced and/or edited the show will provide the media directly to the station airing it. In many cases this is a very high bit-rate, high resolution file. Something akin to Avid's DNxHD format (such as DNxHD145 or 175), or Apple ProRes, or Sony's XDCAM. But despite the higher-than-average bitrate of the file, the resolution is rarely anything higher than 1080p.
Unless you're the editor, and you'd be working with a 1080p file at a bit-rate of 145 or 175 Mbps.
But these formats are not secret, or kept from the general public. You can have the same formats TV stations use.
For example: File based workflows (where the production house turns over the raw media directly), the file would most likely be in the MOV or MXF formats. These files are normally encoded at a bit rate of somewhere between 30 and 50 Mbps (hopefully), and a have resolution between 720 and 1080.
Neither of these file types are hard to come by, and in fact, the MXF file type is listed as a SMPTE standard (SMPTE 377M). But how convenient would it be to sell you a show and make you download a 28GB file or a 32GB USB drive with a single episode of Game of Thrones?
So, it's made available to everybody in a compressed, but still very high quality format: Blu-ray.
These Blu-ray's are normally encoded at a 15-30 Mbit bit-rate, which although less than the raw MXF, is still very high.
Or you could download a slightly more compressed version from some website, or a streaming/OTT service (Apple TV, Netflix, etc).
Source: I work at a TV station.