Employee Benefits (Details) (USD $)	0 Months Ended	12 Months Ended						3 Months Ended
	Dec. 08, 2014	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Mar. 31, 2013
Employee Benefits
Benefit obligation		$ 18,872,000,000		$ 17,089,000,000		$ 18,956,000,000
Projected benefit obligation increase due to adoption of new mortality table		1,300,000,000
Remaining estimated life of plan participants		8 years
Effect of change of 100 basis points in the assumed initial health care cost trend rate
Effect on the aggregate of the service and interest cost components of net periodic post-retirement benefit expense (statements of operations) - Increase		4,000,000
Effect on the aggregate of the service and interest cost components of net periodic post-retirement benefit expense (statements of operations) - Decrease		(3,000,000)
Effect of one-percentage point increase on postretirement benefit obligation		92,000,000
Effect of one-percentage point decrease on postretirement benefit obligation		(82,000,000)
Healthcare cost increase trend rates (as a percent)
Ultimate health care cost trend rate (as a percent)		4.50%
Actuarial assumptions at beginning of year:
Ultimate health care cost trend rate (as a percent)		4.50%
Components of net periodic benefit (income) expense
Expected return on plan assets		(924,000,000)		(935,000,000)
Actuarial assumptions at end of year:
Ultimate health care cost trend rate (as a percent)		4.50%
Change in benefit obligation
Benefit obligation at beginning of year		17,089,000,000		18,956,000,000				18,956,000,000
Benefit obligation at end of year		18,872,000,000		17,089,000,000		18,956,000,000
Change in plan assets
Return on plan assets		1,410,000,000		855,000,000
Settlements	460,000,000			0		0
Target allocation of plan assets
Permitted investment in securities issued by the sponsor company (as a percent)		10.00%
Pension Plans
Employee Benefits
Unfunded status		(2,471,000,000)		(1,055,000,000)
Employer contributions		157,000,000		146,000,000		32,000,000
Benefits paid directly to participants by company		6,000,000		5,000,000		5,000,000
Fair value of plan assets		12,571,000,000		12,346,000,000		12,321,000,000
Benefit obligation		15,042,000,000		13,401,000,000		14,881,000,000
Estimated future benefit payments:
2015		1,061,000,000
2016		1,011,000,000
2017		996,000,000
2018		980,000,000
2019		965,000,000
2020 - 2024		4,568,000,000
Actuarial assumptions at beginning of year:
Rate of compensation increase (as a percent)		3.25%		3.25%		3.25%
Expected long-term rate of return on plan assets (as a percent)		7.50%		7.50%		7.50%
Components of net periodic benefit (income) expense
Service cost		77,000,000		91,000,000		87,000,000
Interest cost		602,000,000		544,000,000		625,000,000
Expected return on plan assets		(891,000,000)		(896,000,000)		(847,000,000)
Settlements		63,000,000		0		0
Recognition of prior service cost		5,000,000		5,000,000		4,000,000
Recognition of actuarial loss		22,000,000		84,000,000		35,000,000
Net periodic pension benefit income		(122,000,000)		(172,000,000)		(96,000,000)
Actuarial assumptions at end of year:
Rate of compensation increase (as a percent)		3.25%		3.25%
Change in benefit obligation
Benefit obligation at beginning of year		13,401,000,000		14,881,000,000		13,596,000,000		14,881,000,000
Service cost		77,000,000		91,000,000		87,000,000
Interest cost		602,000,000		544,000,000		625,000,000
Plan amendments		4,000,000		0		14,000,000
Actuarial loss (gain)		2,269,000,000		(1,179,000,000)		1,565,000,000
Benefits paid by company		(6,000,000)		(5,000,000)		(5,000,000)
Benefits paid from plan assets		(845,000,000)	[1]	(931,000,000)	[1]	(1,001,000,000)	[1]
Benefit obligation at end of year		15,042,000,000		13,401,000,000		14,881,000,000
Change in plan assets
Fair value of plan assets at beginning of year		12,346,000,000		12,321,000,000		11,814,000,000		12,321,000,000
Return on plan assets		1,373,000,000		810,000,000		1,476,000,000
Employer contributions		157,000,000		146,000,000		32,000,000
Benefits paid from plan assets		(845,000,000)	[1]	(931,000,000)	[1]	(1,001,000,000)	[1]
Fair value of plan assets at end of year		12,571,000,000		12,346,000,000		12,321,000,000
Target allocation of plan assets
Expected long-term rate of return on plan assets (as a percent)		7.50%		7.50%		7.50%
Pension Plans | Interest rate sensitive investments
Target allocation of plan assets
Target asset allocation percentage (as a percent)		41.50%
Pension Plans | Investment grade bonds
Employee Benefits
Fair value of plan assets		2,493,000,000	[2]
Change in plan assets
Fair value of plan assets at beginning of year		2,317,000,000	[2]
Fair value of plan assets at end of year		2,493,000,000	[2]
Target allocation of plan assets
Target asset allocation percentage (as a percent)		26.00%
Pension Plans | High yield and emerging market bonds
Target allocation of plan assets
Target asset allocation percentage (as a percent)		10.50%
Pension Plans | Convertible bonds
Employee Benefits
Fair value of plan assets		14,000,000	[3]
Change in plan assets
Fair value of plan assets at beginning of year		389,000,000	[3]
Fair value of plan assets at end of year		14,000,000	[3]
Target allocation of plan assets
Target asset allocation percentage (as a percent)		13.50%
Pension Plans | Diversified strategies
Employee Benefits
Fair value of plan assets		718,000,000	[4]
Change in plan assets
Fair value of plan assets at beginning of year		723,000,000	[4]
Fair value of plan assets at end of year		718,000,000	[4]
Target allocation of plan assets
Target asset allocation percentage (as a percent)		5.00%
Pension Plans | Interest rate investments with higher returns
Target allocation of plan assets
Target asset allocation percentage (as a percent)		58.50%
Pension Plans | U.S. stocks
Employee Benefits
Fair value of plan assets		1,476,000,000	[5]
Change in plan assets
Fair value of plan assets at beginning of year		1,500,000,000	[5]
Fair value of plan assets at end of year		1,476,000,000	[5]
Target allocation of plan assets
Target asset allocation percentage (as a percent)		14.50%
Pension Plans | Developed market Non-U.S. stocks
Employee Benefits
Fair value of plan assets		1,553,000,000	[1]
Change in plan assets
Fair value of plan assets at beginning of year		1,458,000,000	[1]
Fair value of plan assets at end of year		1,553,000,000	[1]
Target allocation of plan assets
Target asset allocation percentage (as a percent)		14.50%
Pension Plans | Diversified multi-asset classes
Target allocation of plan assets
Target asset allocation percentage (as a percent)		11.00%
Pension Plans | Other
Target allocation of plan assets
Target asset allocation percentage (as a percent)		10.50%
Pension Plans | Real estate
Employee Benefits
Fair value of plan assets		699,000,000	[6]
Change in plan assets
Fair value of plan assets at beginning of year		571,000,000	[6]
Fair value of plan assets at end of year		699,000,000	[6]
Target allocation of plan assets
Target asset allocation percentage (as a percent)		8.00%
Pension Plans | Minimum
Actuarial assumptions at beginning of year:
Discount rate (as a percent)		4.20%		3.50%		4.25%
Actuarial assumptions at end of year:
Discount rate (as a percent)		3.50%		4.20%
Pension Plans | Maximum
Actuarial assumptions at beginning of year:
Discount rate (as a percent)		5.10%		4.20%		5.10%
Actuarial assumptions at end of year:
Discount rate (as a percent)		4.10%		5.10%
Qualified Pension Plans
Employee Benefits
Amortization period of the plan shortfall		7 years
Unfunded status		(2,400,000,000)
Employer contributions		157,000,000
Change in plan assets
Employer contributions		157,000,000
Non-Qualified Pension Plans
Employee Benefits
Benefits paid directly to participants by company		6,000,000
Estimated future benefit payments:
2015		6,000,000
Change in benefit obligation
Benefits paid by company		(6,000,000)
Qwest Qualified Pension Plan
Employee Benefits
Termination settlement threshold	418,000,000
Estimated future benefit payments:
Defined Benefit Plan, Settlements, Benefit Obligation	(460,000,000)					0		0
Components of net periodic benefit (income) expense
Settlements		63,000,000
Post-Retirement Benefit Plans
Employee Benefits
Unfunded status		(3,477,000,000)		(3,153,000,000)
Employer contributions		0
Benefits paid directly to participants by company		166,000,000		266,000,000		268,000,000
Fair value of plan assets		353,000,000		535,000,000		626,000,000
Benefits paid, net of participant contributions and direct subsidy receipts		88,000,000
Expected future benefit payments not payable by the trust, net of participant contributions and direct subsidiaries		139,000,000
Benefit obligation		3,830,000,000		3,688,000,000		4,075,000,000
Healthcare cost increase trend rates (as a percent)
Health care cost trend rate (as a percent)		6.00%
Ultimate health care cost trend rate (as a percent)		4.50%		4.50%		5.00%
Estimated future benefit payments:
2015		309,000,000
2016		300,000,000
2017		292,000,000
2018		285,000,000
2019		279,000,000
2020 - 2024		1,276,000,000
Medicare Part D Subsidy Receipts
2015		(7,000,000)
2016		(7,000,000)
2017		(7,000,000)
2018		(7,000,000)
2019		(7,000,000)
2020 - 2024		(31,000,000)
Actuarial assumptions at beginning of year:
Discount rate (as a percent)		4.50%		3.60%
Expected long-term rate of return on plan assets (as a percent)		7.50%
Ultimate health care cost trend rate (as a percent)		4.50%		4.50%		5.00%
Components of net periodic benefit (income) expense
Service cost		22,000,000		24,000,000		22,000,000
Interest cost		159,000,000		140,000,000		173,000,000
Expected return on plan assets		(33,000,000)		(39,000,000)		(45,000,000)
Recognition of prior service cost		20,000,000		0		0
Recognition of actuarial loss		0		4,000,000		0
Net periodic pension benefit income		168,000,000		129,000,000		150,000,000
Actuarial assumptions at end of year:
Discount rate (as a percent)		3.80%		4.50%
Initial health care cost trend rate (as a percent)						8.00%
Ultimate health care cost trend rate (as a percent)		4.50%		4.50%		5.00%
Change in benefit obligation
Benefit obligation at beginning of year		3,688,000,000		4,075,000,000		3,930,000,000		4,075,000,000
Service cost		22,000,000		24,000,000		22,000,000
Interest cost		159,000,000		140,000,000		173,000,000
Participant contributions		69,000,000		96,000,000		86,000,000
Plan amendments		23,000,000		141,000,000		0
Direct subsidy receipts		9,000,000		13,000,000		19,000,000
Actuarial loss (gain)		245,000,000		(399,000,000)		260,000,000
Benefits paid by company		(166,000,000)		(266,000,000)		(268,000,000)
Benefits paid from plan assets		(219,000,000)		(136,000,000)		(147,000,000)
Benefit obligation at end of year		3,830,000,000		3,688,000,000		4,075,000,000
Change in plan assets
Fair value of plan assets at beginning of year		535,000,000		626,000,000		693,000,000		626,000,000
Return on plan assets		37,000,000		45,000,000		80,000,000
Employer contributions		0
Benefits paid from plan assets		(219,000,000)		(136,000,000)		(147,000,000)
Fair value of plan assets at end of year		353,000,000		535,000,000		626,000,000
Target allocation of plan assets
Expected long-term rate of return on plan assets (as a percent)		7.50%
Post-Retirement Benefit Plans | Investment grade bonds
Employee Benefits
Fair value of plan assets		77,000,000	[2]	77,000,000
Change in plan assets
Fair value of plan assets at end of year		77,000,000	[2]	77,000,000
Post-Retirement Benefit Plans | Diversified strategies
Employee Benefits
Fair value of plan assets		89,000,000	[4]	86,000,000
Change in plan assets
Fair value of plan assets at end of year		89,000,000	[4]	86,000,000
Post-Retirement Benefit Plans | U.S. stocks
Employee Benefits
Fair value of plan assets		35,000,000	[5]	56,000,000
Change in plan assets
Fair value of plan assets at end of year		35,000,000	[5]	56,000,000
Post-Retirement Benefit Plans | Developed market Non-U.S. stocks
Employee Benefits
Fair value of plan assets		33,000,000	[1]	58,000,000
Change in plan assets
Fair value of plan assets at end of year		33,000,000	[1]	58,000,000
Post-Retirement Benefit Plans | Real estate
Employee Benefits
Fair value of plan assets		28,000,000	[6]	34,000,000
Change in plan assets
Fair value of plan assets at end of year		$ 28,000,000	[6]	$ 34,000,000
Post-Retirement Benefit Plans | Equity Securities
Target allocation of plan assets
Target asset allocation percentage (as a percent)		30.00%
Post-Retirement Benefit Plans | Non-equity investments
Target allocation of plan assets
Target asset allocation percentage (as a percent)		70.00%
Post-Retirement Benefit Plans | Minimum
Healthcare cost increase trend rates (as a percent)
Annual decrease in health care cost trend rate (as a percent)		(0.25%)
Ultimate health care cost trend rate (as a percent)				4.50%
Actuarial assumptions at beginning of year:
Discount rate (as a percent)						4.60%
Expected long-term rate of return on plan assets (as a percent)		6.00%		6.00%		6.00%
Ultimate health care cost trend rate (as a percent)				4.50%
Actuarial assumptions at end of year:
Initial health care cost trend rate (as a percent)		6.00%		6.50%
Ultimate health care cost trend rate (as a percent)				4.50%
Target allocation of plan assets
Expected long-term rate of return on plan assets (as a percent)		6.00%		6.00%		6.00%
Post-Retirement Benefit Plans | Maximum
Healthcare cost increase trend rates (as a percent)
Annual decrease in health care cost trend rate (as a percent)		(0.15%)
Actuarial assumptions at beginning of year:
Discount rate (as a percent)						4.80%
Expected long-term rate of return on plan assets (as a percent)		7.50%		7.30%		7.50%
Actuarial assumptions at end of year:
Initial health care cost trend rate (as a percent)		6.50%		7.00%
Target allocation of plan assets
Expected long-term rate of return on plan assets (as a percent)		7.50%		7.30%		7.50%

[1] Non-U.S. stocks represent investments in stocks of companies based in developed countries outside the U.S. as well as commingled funds. The valuation inputs for non-U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above. These commingled funds can be redeemed at NAV within a year of the financial statement date and are classified as Level 2.

[2] Investment grade bonds represent investments in fixed income securities as well as commingled bond funds comprised of U.S. Treasury securities, agencies, corporate bonds, mortgage-backed securities, asset-backed securities and commercial mortgage-backed securities. Treasury securities are valued at the bid price reported in the active market in which the security is traded and are classified as Level 1. The valuation inputs of other investment grade bonds primarily utilize observable market information and are based on a spread to U.S. Treasury securities and consider yields available on comparable securities of issuers with similar credit ratings. The primary observable inputs include references to the new issue market for similar securities, the secondary trading markets and dealer quotes. Option adjusted spread models are utilized to evaluate securities such as asset backed securities that have early redemption features. These securities are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying fixed income securities using the same valuation inputs described above. The commingled funds can be redeemed at NAV within a year of the financial statement date and are classified as Level 2.

[3] Convertible bonds primarily represent investments in corporate debt securities that have features that allow the debt to be converted into equity securities under certain circumstances. The valuation inputs for the individual convertible bonds primarily utilize observable market information including a spread to U.S. Treasuries and the value and volatility of the underlying equity security. Convertible bonds are classified as Level 2.

[4] Diversified strategies represent an investment in a commingled fund that primarily has exposures to global government, corporate and inflation linked bonds, global stocks and commodities. The commingled fund is valued at NAV based on the market value of the underlying investments. The valuation inputs utilize observable market information including published prices for exchange traded securities, bid prices for government bonds, and spreads and yields available for comparable fixed income securities with similar credit ratings. This fund can be redeemed at NAV within a year of the financial statement date and is classified as Level 2.

[5] U.S. stocks represent investments in stocks of U.S. based companies as well as commingled U.S. stock funds. The valuation inputs for U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above. These commingled funds can be redeemed at NAV within a year of the financial statement date and are classified as Level 2.

[6] Real estate represents investments in commingled funds and limited partnerships that invest in a diversified portfolio of real estate properties. These investments are valued at NAV according to the valuation policy of each fund or partnership, subject to prevailing accounting and other regulatory guidelines. The valuation inputs of the underlying properties are generally based on third-party appraisals that use comparable sales or a projection of future cash flows to determine fair value. Real estate investments that can be redeemed at NAV within a year of the financial statement date are classified as Level 2. Real estate investments that cannot be redeemed at NAV or that cannot be redeemed at NAV within a year of the financial statement date are classified as Level 3.