Tuesday night's "American Idol" season debut easily beat out the competition to become the No. 1 show for the night among adults 18-49 and total viewers, posting a 11.6 rating/28 share among viewers 18-49 and drawing 30.1 million viewers, according to preliminary Nielsen Media Research information.

The Tuesday-night season opener, however, dipped in the ratings for a second year in a row. For more "Idol" ratings info, click here. While the series debuted to lower numbers comparatively, last night's viewership marks the highest-rated telecast and night of the TV season. Fox out-rated the other four major broadcast networks combined by 17% in the demographic.

CBS took second place for the night, scoring a 3.5/8 and 16.3 million viewers. New episodes of "NCIS," "The Mentalist" and "Without a Trace" were about on par for the season-to-date despite the fierce competition from "Idol." The first two showed slight decreases from the week before against "Idol," while "Trace" posted a 12% increase.

NBC placed third for the night (3.3/8, 9.1 million) with new episodes of "The Biggest Loser" and "Law & Order: SVU." Although "Loser" showed a 27% decrease from last week due to "Idol" competition, the series was up 10% compared with last year against "Idol's" debut.

New episodes of "Scrubs" on ABC scored a 2.2/5 at both 9 and 9:30 p.m., down 29% and 32%, respectively, from their debut on the network last week. In the 8 p.m. hour "Homeland Security U.S.A." was down 22% from last week, while "Primetime: What Would You Do" showed a 4% increase. ABC finished the night fourth with a 2.3/6 (5.9 million).

The CW finished fifth with an average 0.8/2 (1.7 million). "90210" was down 21% from last week's episode, while "Privileged" dropped 38% from last week against "Idol" competition. The network averaged a 1.4 rating among women 18-34.

	8	8:30	9	9:30	10	10:30
2.3 / 6	Homeland Security U.S.A. 1.8 / 5 6 million		Scrubs 2.2 / 5 4.6 mil	Scrubs 2.2 / 5 4.3 mil	Primetime: What Would You Do? 2.8 / 7 7.3 mil
3.5 / 8	NCIS 3.7 / 9 18.5 mil		The Mentalist 3.8 / 9 18.1 mil		Without a Trace 2.9 / 7 12.4 mil
11.6 / 28	American Idol 11.6 / 28 30.1 mil				No Programming
3.3 / 8	The Biggest Loser 3.3 / 8 8.8 mil				Law & Order: SVU 3.5 / 9 9.7 mil
0.8 / 2	90210 1.1 / 3 2.2 mil		Privileged 0.5 / 1 1.1 mil		No Programming

Source: Nielsen Media Research

*Ratings are specified in the 18- to 49-year-old demographic and viewership in P2+.

A note about ratings: Ratings are expressed as percentages of Nielsen's estimated 114.5 million U.S. television households. The first number, the rating, is a percentage of households tuned into a specific program at a specific time.

The second number, the share, is a percentage of households with televisions in use tuned into that same program. For example, if a show obtains a 10.2/16, this means that 10.2% of all U.S. households tuned into the program at some point during the broadcast. Meanwhile, 16% of all households watching television during the time period viewed the program at some point. Ratings are broken down further by demographic, as networks sell advertising time based on the makeup of the audience.