Answer by taking a quote from the following article:

Peter Dennis Blandford Townshend (born 19 May 1945) is an English musician, singer, songwriter, and multi-instrumentalist, best known as the lead guitarist, backing vocalist, and principal songwriter for the rock band the Who. His career with the Who spans over 50 years, during which time the band grew to be considered one of the most influential bands of the 20th century. Townshend is the main songwriter for the Who, having written well over 100 songs for the band's 11 studio albums, including concept albums and the rock operas Tommy and Quadrophenia, plus popular rock radio staples such as Who's Next, and dozens more that appeared as non-album singles, bonus tracks on reissues, and tracks on rarities compilations such as Odds & Sods (1974). He has also written more than 100 songs that have appeared on his solo albums, as well as radio jingles and television theme songs.

In addition to his work with the Who, Townshend has been sporadically active as a solo recording artist. Between 1969 and 1971 Townshend, along with other devotees to Meher Baba, recorded a trio of albums devoted to his teachings: Happy Birthday, I Am, and With Love. In response to bootlegging of these, he compiled his personal highlights (and "Evolution", a collaboration with Ronnie Lane), and released his first major-label solo title, 1972's Who Came First. It was a moderate success and featured demos of Who songs as well as a showcase of his acoustic guitar talents. He collaborated with The Faces' bassist and fellow Meher Baba devotee Ronnie Lane on a duet album (1977's Rough Mix). Townshend's solo breakthrough, following the death of Who drummer Keith Moon, was the 1980 release Empty Glass, which included a top-10 single, "Let My Love Open the Door" and "Rough Boys". This release was followed in 1982 by All the Best Cowboys Have Chinese Eyes, which included the popular radio track "Slit Skirts". While not a huge commercial success, noted music critic Timothy Duggan listed it as "Townshend's most honest and introspective work since Quadrophenia." Through the rest of the 1980s and early 1990s Townshend would again experiment with the rock opera and related formats, releasing several story-based albums including White City: A Novel (1985), The Iron Man: A Musical (1989), and Psychoderelict (1993). Townshend also got the chance to play with his hero Hank Marvin for Paul McCartney's "Rockestra" sessions, along with other respected rock musicians such as David Gilmour, John Bonham and Ronnie Lane.  Townshend has also recorded several concert albums, including one featuring a supergroup he assembled called Deep End, who performed just three concerts and a television show session for The Tube, to raise money for a charity supporting drug addicts. In 1993 he and Des McAnuff wrote and directed the Broadway adaptation of the Who album Tommy, as well as a less successful stage musical based on his solo album The Iron Man, based upon the book by Ted Hughes. McAnuff and Townshend later co-produced the animated film The Iron Giant, also based on the Hughes story.  A production described as a Townshend rock opera and titled The Boy Who Heard Music debuted as part of Vassar College's Powerhouse Summer Theater program in July 2007.  On 2 September 2017 in Lenox, Massachusetts, Pete Townshend embarked with fellow singer and musician Billy Idol, tenor Alfie Boeon and an orchestra on a short (5-date) "Classic Quadrophenia" US tour which ended on 16 September 2017 in Los Angeles, California.

What have Townshend and Idol done together?
) "Classic Quadrophenia" US tour which ended on 16 September 2017 in Los Angeles, California.