Restructuring and Other Items - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014 aircraft
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	$ 716	$ 402	$ 452
Fleet, facilities and other
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	758	402	293
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	71	0	237
Comair employee severance
Restructuring Cost and Reserve [Line Items]
Restructuring and other items			66
Routes and slots
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	0	0	(78)
Favorable settlement of outstanding litigation
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	67
Insurance settlement
Restructuring Cost and Reserve [Line Items]
Restructuring and other items	46
Delta employee severance | Severance and related costs
Restructuring Cost and Reserve [Line Items]
Entity number of employees (more than 2,000 for voluntary severance programs)			2,000
Comair employee severance | Severance and related costs
Restructuring Cost and Reserve [Line Items]
Entity number of employees (more than 2,000 for voluntary severance programs)			1,700
Other postretirement and postemployment benefits
Restructuring Cost and Reserve [Line Items]
Defined benefit plan, other costs	$ 0	$ 0	$ 116
B-747-400
Restructuring Cost and Reserve [Line Items]
Number of aircraft designated for retirement				16
Fleet retirement, time horizon				3 years
Number of aircraft retired				3