Erj-170 captain reported a possible wake vortex encounter on arrival to ord.

Attributes
ACN	1114807
Time
Date	201309
Local Time Of Day	1201-1800
Place
Locale Reference	ZAU.ARTCC
State Reference	IL
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR BULLZ
Aircraft 2
Make Model Name	B777 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR BULLZ
Person 1
Function	Captain Pilot Flying
Events
Anomaly	Inflight Event / Encounter Wake Vortex Encounter Inflight Event / Encounter Weather / Turbulence

Narrative:

Descending through approximately 28;000 ft aircraft hit clear air turbulence; but possible wake turbulence; [which] 'abruptly' rolled the aircraft to a 60-70 degrees bank to the left followed by severe turbulence. Flight attendant stated it lifted the galley cart off the ground; which caused a drink to spill [on] a passenger. [We] immediately slowed aircraft from 300 KTS through 270 KTS. There were no clouds; traffic; nor any reports of this on the bullz arrival. Mfd was set on expanded traffic with a 12.5 mile range. We could have been possibly following a heavy 777. No one was hurt and a report was given to air traffic control after he questioned our speed being different than assigned.

Original NASA ASRS Text

Title: ERJ-170 Captain reported a possible wake vortex encounter on arrival to ORD.

Narrative: Descending through approximately 28;000 FT aircraft hit clear air turbulence; but possible wake turbulence; [which] 'abruptly' rolled the aircraft to a 60-70 degrees bank to the left followed by severe turbulence. Flight Attendant stated it lifted the galley cart off the ground; which caused a drink to spill [on] a passenger. [We] immediately slowed aircraft from 300 KTS through 270 KTS. There were no clouds; traffic; nor any reports of this on the BULLZ arrival. MFD was set on expanded traffic with a 12.5 mile range. We could have been possibly following a heavy 777. No one was hurt and a report was given to Air Traffic Control after he questioned our speed being different than assigned.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.