AMERICAN TOWER CORP /MA/ - 10-Q filing on 2015-04-30

Long-Term Obligations (Narrative) (Details)	3 Months Ended						0 Months Ended								3 Months Ended		0 Months Ended	1 Months Ended	3 Months Ended		1 Months Ended	3 Months Ended		0 Months Ended	1 Months Ended	0 Months Ended		1 Months Ended
Long-Term Obligations (Narrative) (Details)	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 Mexican loan Unsecured Debt USD ($)	Mar. 31, 2015 Mexican loan Unsecured Debt MXN	Mar. 31, 2015 Seven Point Zero Zero Percent Senior Notes Senior Notes USD ($)	Feb. 12, 2015 Four Point Six Two Five Percent Senior Notes Senior Notes USD ($)	Mar. 31, 2015 Four Point Six Two Five Percent Senior Notes Senior Notes USD ($)	Nov. 19, 2014 BR Towers Credit Facility Unsecured Debt BRL	Mar. 31, 2015 Credit Facility 2014 Revolving Credit Facility USD ($)	Mar. 31, 2015 Credit Facility 2013 Revolving Credit Facility USD ($)	Feb. 20, 2015 Credit Facility 2013 Revolving Credit Facility USD ($)	Mar. 31, 2015 Term Loan 2013 Unsecured Debt USD ($)	Feb. 20, 2015 Term Loan 2013 Unsecured Debt USD ($)	Mar. 31, 2015 Senior Notes Four Point Six Two Five Percent Senior Notes USD ($)	Mar. 31, 2015 Revolving Credit Facility USD ($)	Sep. 20, 2014 Revolving Credit Facility Credit Facility 2014	Jun. 30, 2013 Revolving Credit Facility Credit Facility 2014	Mar. 31, 2015 Revolving Credit Facility Credit Facility 2014 USD ($) renewal_periods	Feb. 20, 2015 Revolving Credit Facility Credit Facility 2014 USD ($)	Jun. 30, 2013 Revolving Credit Facility Credit Facility 2013 renewal_periods	Mar. 31, 2015 Revolving Credit Facility Credit Facility 2013 USD ($)	Mar. 31, 2015 London Interbank Offered Rate (LIBOR) Term Loan 2013 Unsecured Debt	Sep. 20, 2014 London Interbank Offered Rate (LIBOR) Revolving Credit Facility Credit Facility 2014	Jun. 30, 2013 London Interbank Offered Rate (LIBOR) Revolving Credit Facility Credit Facility 2013	Apr. 29, 2015 Subsequent Event Seven Point Zero Zero Percent Senior Notes Senior Notes USD ($)	Apr. 29, 2015 Subsequent Event Seven Point Zero Zero Percent Senior Notes Senior Notes	Apr. 30, 2015 Subsequent Event Revolving Credit Facility Credit Facility 2013 USD ($)	Feb. 20, 2015 Second measurement period Credit Facility 2014 Revolving Credit Facility	Feb. 20, 2015 Second measurement period Credit Facility 2013 Revolving Credit Facility	Feb. 20, 2015 Second measurement period Term Loan 2013 Unsecured Debt	Feb. 20, 2015 Third measurement period Credit Facility 2014 Revolving Credit Facility	Feb. 20, 2015 Third measurement period Credit Facility 2013 Revolving Credit Facility	Feb. 20, 2015 Third measurement period Term Loan 2013 Unsecured Debt	Feb. 20, 2015 Fourth measurement period Credit Facility 2014 Revolving Credit Facility	Feb. 20, 2015 Fourth measurement period Credit Facility 2013 Revolving Credit Facility	Feb. 20, 2015 Fourth measurement period Term Loan 2013 Unsecured Debt
Debt Instrument [Line Items]
Long-term Debt													$ 2,000,000,000
Long-term Debt, Current Maturities	789,152,000		897,624,000	254,600,000	3,900,000,000	500,000,000
Proceeds from Lines of Credit	3,150,000,000	0														2,100,000,000						1,000,000,000						1,600,000,000
Bridge Loan					5,200,000,000
Stated percentage interest rate						7.00%									4.625%												7.00%
Debt Instrument, Redemption Price, Percentage							100.5898%
Repayments of Senior Debt							613,600,000																			571,700,000
Interest Paid	77,654,000		130,265,000					10,000,000
Extinguishment of Debt, Gain (Loss), Net of Tax	3,725,000	238,000													3,700,000
Long-term Debt, Fair Value	16,300,000,000		15,000,000,000						48,100,000
Maximum revolving loan commitments												3,500,000,000								2,500,000,000
Line of credit facility, optional additional commitments												750,000,000
Term Loan, optional additional commitments														500,000,000
Line of Credit Facility, Maximum Borrowing Capacity												2,750,000,000								2,000,000,000
Repayments of Lines of Credit																			1,300,000,000			615,000,000
Long-term Line of Credit										1,980,000,000	400,000,000
Letters of Credit Outstanding, Amount										7,500,000												3,200,000
Debt Instrument, Term																		5 years			5 years
Number of Annual Renewal Periods																			2		2
Debt instrument, length of renewal period																						1 year
Debt Instrument, Basis Spread on Variable Rate																							1.25%	1.25%	1.25%
Maximum incremental term loan commitment														$ 1,000,000,000
Line of Credit Facility, Commitment Fee Percentage																	0.15%				0.15%
Ratio of total debt to EBITDA																													7.25	7.25	7.25	7.00	7.00	7.00	6.00	6.00	6.00