This is a feature that MS Word has had for a long time, which makes a huge productivity departure to anyone who is writing long documents.
Basically, instead of formattting each sub-heading individually (eg making it bold, 12 pt together with underlined), you lot lot only rank inwards i trial what the rules for that "heading2" is (eg bold, 12 pt together with underlined), together with as well as so apply "heading2" to whatever text that you lot lot wishing to await like this. The time-saving comes when construct a change. For example, when you lot lot realise that underlining is for typewriters, instead of having to modify each sub-heading individually, you lot lot only modify heading2 to suffer (say) bold together with fourteen asking - together with all the same modify is made to every menage where you've used "heading2".
I don't know the the improver of Styles to Docs way they testament suffer added to Blogger's Post-editor anytime soon. But it may touching loading Word documents to Blogger via Google Docs. I haven't tested yet, so don't know if Word's styles testament suffer kept when the document is converted - only I'd hope that they would, given that it's a rattling mature feature inwards Word.
The interesting endure testament come upwards upwardly when you lot lot either copy-and-paste or notice from Docs to Blogger: is the formatting itself transferred over, or only the trend name?
My guess, without testing, is that for copy-and-paste, it mightiness only suffer the trend name. If that's right, together with so to construct the Word-to-Docs-to-Blogger conversion work, you lot lot testament demand to add CSS rules to your blog, using the same trend names used inwards Docs.
And if you lot lot bring a lot of email subscribers, holler upwardly head that the messages they cause got practice not bring your blog's stylesheet applied to them. (I experimented with various header trend options inwards BloggerHAT, only eventually gave us together with followed the trial of other big-time bloggers together with applied the formatting manually, for only this reason: no thing what I tried, my email-subscription messages looked bad,)
(BTW: If you lot lot know a way to apply a stylesheet to emails sent by times Feedburner, or fifty-fifty by times Blogger, together with so I'd honey to accept away head most it.)